diff --git a/Example/SyncKitCoreData/SyncKitCoreDataiOS.xcodeproj/project.pbxproj b/Example/SyncKitCoreData/SyncKitCoreDataiOS.xcodeproj/project.pbxproj
index ed4d1709..c3628af2 100644
--- a/Example/SyncKitCoreData/SyncKitCoreDataiOS.xcodeproj/project.pbxproj
+++ b/Example/SyncKitCoreData/SyncKitCoreDataiOS.xcodeproj/project.pbxproj
@@ -10,6 +10,7 @@
 		649AF58E1EE31D07004A9220 /* QSCloudKitSyncModel.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 649AF58C1EE31D07004A9220 /* QSCloudKitSyncModel.xcdatamodeld */; };
 		64AE80871FD2F9CD004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 64AE80851FD2F9CD004BFEA4 /* QSCloudKitSynchronizer+Private.h */; };
 		64AE80881FD2F9CD004BFEA4 /* QSCloudKitSynchronizer+Private.m in Sources */ = {isa = PBXBuildFile; fileRef = 64AE80861FD2F9CD004BFEA4 /* QSCloudKitSynchronizer+Private.m */; };
+		64DFFAB51FEED0640072B8C3 /* QSKeyValueStore.h in Headers */ = {isa = PBXBuildFile; fileRef = 64DFFAB41FEED0640072B8C3 /* QSKeyValueStore.h */; };
 		64F292311ECEA5F1000026F1 /* SyncKitCoreData.h in Headers */ = {isa = PBXBuildFile; fileRef = 64F2922F1ECEA5F1000026F1 /* SyncKitCoreData.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		64F2923B1ECEA627000026F1 /* QSChangeManager.h in Headers */ = {isa = PBXBuildFile; fileRef = 64F292371ECEA627000026F1 /* QSChangeManager.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		64F2923C1ECEA627000026F1 /* QSCloudKitSynchronizer.h in Headers */ = {isa = PBXBuildFile; fileRef = 64F292381ECEA627000026F1 /* QSCloudKitSynchronizer.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -47,6 +48,7 @@
 		649AF58D1EE31D07004A9220 /* QSCloudKitSyncModel.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = QSCloudKitSyncModel.xcdatamodel; sourceTree = "<group>"; };
 		64AE80851FD2F9CD004BFEA4 /* QSCloudKitSynchronizer+Private.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = "QSCloudKitSynchronizer+Private.h"; path = "../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.h"; sourceTree = "<group>"; };
 		64AE80861FD2F9CD004BFEA4 /* QSCloudKitSynchronizer+Private.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; name = "QSCloudKitSynchronizer+Private.m"; path = "../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.m"; sourceTree = "<group>"; };
+		64DFFAB41FEED0640072B8C3 /* QSKeyValueStore.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = QSKeyValueStore.h; path = ../../../SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h; sourceTree = "<group>"; };
 		64F2922C1ECEA5F1000026F1 /* SyncKitCoreData.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = SyncKitCoreData.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		64F2922F1ECEA5F1000026F1 /* SyncKitCoreData.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SyncKitCoreData.h; sourceTree = "<group>"; };
 		64F292301ECEA5F1000026F1 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
@@ -119,6 +121,7 @@
 				64F2925B1ECEA6DD000026F1 /* NSManagedObjectContext+QSFetch.m */,
 				64F2925C1ECEA6DD000026F1 /* QSCloudKitSynchronizer+CoreData.m */,
 				64F2925D1ECEA6DD000026F1 /* QSCoreDataChangeManager.m */,
+				64DFFAB41FEED0640072B8C3 /* QSKeyValueStore.h */,
 				64F2925E1ECEA6DD000026F1 /* QSCoreDataStack.m */,
 				64F2925F1ECEA6DD000026F1 /* QSEntityIdentifierUpdateMigrationPolicy.m */,
 				64F292601ECEA6DD000026F1 /* QSManagedObjectContext.m */,
@@ -176,6 +179,7 @@
 				64F2923D1ECEA627000026F1 /* QSPrimaryKey.h in Headers */,
 				64F2923E1ECEA627000026F1 /* SyncKitLog.h in Headers */,
 				64F292431ECEA67A000026F1 /* QSCloudKitSynchronizer+CoreData.h in Headers */,
+				64DFFAB51FEED0640072B8C3 /* QSKeyValueStore.h in Headers */,
 				64F292441ECEA67A000026F1 /* QSCoreDataChangeManager.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/Example/SyncKitCoreDataExample.xcodeproj/project.pbxproj b/Example/SyncKitCoreDataExample.xcodeproj/project.pbxproj
index ed7319ae..dc753c64 100644
--- a/Example/SyncKitCoreDataExample.xcodeproj/project.pbxproj
+++ b/Example/SyncKitCoreDataExample.xcodeproj/project.pbxproj
@@ -37,6 +37,7 @@
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 		644B20351D4811BE00C131CD /* QSExample.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 644B20331D4811BE00C131CD /* QSExample.xcdatamodeld */; };
 		64AEF0001D4E8E01003729A5 /* QSCompanyTableViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 64AEEFFF1D4E8E01003729A5 /* QSCompanyTableViewController.m */; };
+		64DFFAB11FED35F90072B8C3 /* QSMockKeyValueStore.m in Sources */ = {isa = PBXBuildFile; fileRef = 64DFFAB01FED35F90072B8C3 /* QSMockKeyValueStore.m */; };
 		6D49297B61E7030F49DDD104 /* libPods-SyncKitCoreDataExampleTests.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 22D5A5F41A6AFB038AD7DDA6 /* libPods-SyncKitCoreDataExampleTests.a */; };
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 /* End PBXBuildFile section */
@@ -110,6 +111,8 @@
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 		64AEEFFE1D4E8E01003729A5 /* QSCompanyTableViewController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = QSCompanyTableViewController.h; sourceTree = "<group>"; };
 		64AEEFFF1D4E8E01003729A5 /* QSCompanyTableViewController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = QSCompanyTableViewController.m; sourceTree = "<group>"; };
+		64DFFAAF1FED35F90072B8C3 /* QSMockKeyValueStore.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = QSMockKeyValueStore.h; sourceTree = "<group>"; };
+		64DFFAB01FED35F90072B8C3 /* QSMockKeyValueStore.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = QSMockKeyValueStore.m; sourceTree = "<group>"; };
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 		873B8AEA1B1F5CCA007FD442 /* Main.storyboard */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = file.storyboard; path = Main.storyboard; sourceTree = "<group>"; };
@@ -230,6 +233,8 @@
 				64000CAA1D451F5A006ACD20 /* QSObject.m */,
 				644B202D1D480F1700C131CD /* QSCoreDataChangeManagerTests.m */,
 				64488A541F3BA2C000755D8E /* QSCompany.1739C6A5-C07E-48A5-B83E-AB07694F23DF */,
+				64DFFAAF1FED35F90072B8C3 /* QSMockKeyValueStore.h */,
+				64DFFAB01FED35F90072B8C3 /* QSMockKeyValueStore.m */,
 			);
 			path = Tests;
 			sourceTree = "<group>";
@@ -551,6 +556,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				641F76DE1ED3EBDA00107A88 /* QSCloudKitSynchronizerTests.m in Sources */,
+				64DFFAB11FED35F90072B8C3 /* QSMockKeyValueStore.m in Sources */,
 				6409659F1EDF158D005BCF0F /* QSExample2.xcdatamodeld in Sources */,
 				64377B0B1ED6D394003FB86F /* QSMockDatabase.m in Sources */,
 				64377B0C1ED6D397003FB86F /* QSObject.m in Sources */,
diff --git a/Example/SyncKitCoreDataOSX/SyncKitCoreDataOSX.xcodeproj/project.pbxproj b/Example/SyncKitCoreDataOSX/SyncKitCoreDataOSX.xcodeproj/project.pbxproj
index 9a01fcf5..ba14c183 100644
--- a/Example/SyncKitCoreDataOSX/SyncKitCoreDataOSX.xcodeproj/project.pbxproj
+++ b/Example/SyncKitCoreDataOSX/SyncKitCoreDataOSX.xcodeproj/project.pbxproj
@@ -41,6 +41,7 @@
 		644B0F631ED13D85003B0C51 /* SyncKitLog.h in Headers */ = {isa = PBXBuildFile; fileRef = 644B0F5D1ED13D85003B0C51 /* SyncKitLog.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		64AE808F1FD2FB63004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 64AE808D1FD2FB62004BFEA4 /* QSCloudKitSynchronizer+Private.h */; };
 		64AE80901FD2FB63004BFEA4 /* QSCloudKitSynchronizer+Private.m in Sources */ = {isa = PBXBuildFile; fileRef = 64AE808E1FD2FB63004BFEA4 /* QSCloudKitSynchronizer+Private.m */; };
+		64DFFAB31FEED05E0072B8C3 /* QSKeyValueStore.h in Headers */ = {isa = PBXBuildFile; fileRef = 64DFFAB21FEED05D0072B8C3 /* QSKeyValueStore.h */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -80,6 +81,7 @@
 		644B0F5D1ED13D85003B0C51 /* SyncKitLog.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = SyncKitLog.h; path = ../../../SyncKit/Classes/QSSynchronizer/SyncKitLog.h; sourceTree = "<group>"; };
 		64AE808D1FD2FB62004BFEA4 /* QSCloudKitSynchronizer+Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "QSCloudKitSynchronizer+Private.h"; path = "../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.h"; sourceTree = "<group>"; };
 		64AE808E1FD2FB63004BFEA4 /* QSCloudKitSynchronizer+Private.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = "QSCloudKitSynchronizer+Private.m"; path = "../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.m"; sourceTree = "<group>"; };
+		64DFFAB21FEED05D0072B8C3 /* QSKeyValueStore.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = QSKeyValueStore.h; path = ../../../SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -115,6 +117,7 @@
 				644B0F581ED13D85003B0C51 /* QSChangeManager.h */,
 				644B0F591ED13D85003B0C51 /* QSCloudKitSynchronizer.h */,
 				644B0F5A1ED13D85003B0C51 /* QSCloudKitSynchronizer.m */,
+				64DFFAB21FEED05D0072B8C3 /* QSKeyValueStore.h */,
 				644B0F5B1ED13D85003B0C51 /* QSPrimaryKey.h */,
 				644B0F5C1ED13D85003B0C51 /* QSSyncedEntityState.h */,
 				644B0F5D1ED13D85003B0C51 /* SyncKitLog.h */,
@@ -176,6 +179,7 @@
 				644B0F4A1ED13D7E003B0C51 /* QSManagedObjectContext.h in Headers */,
 				644B0F4E1ED13D7E003B0C51 /* QSPendingRelationship+CoreDataProperties.h in Headers */,
 				644B0F461ED13D7D003B0C51 /* QSCoreDataStack.h in Headers */,
+				64DFFAB31FEED05E0072B8C3 /* QSKeyValueStore.h in Headers */,
 				644B0F441ED13D7D003B0C51 /* QSCoreDataChangeManager.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/Example/SyncKitRealm/SyncKitRealmiOS.xcodeproj/project.pbxproj b/Example/SyncKitRealm/SyncKitRealmiOS.xcodeproj/project.pbxproj
index 56e3a720..45876245 100644
--- a/Example/SyncKitRealm/SyncKitRealmiOS.xcodeproj/project.pbxproj
+++ b/Example/SyncKitRealm/SyncKitRealmiOS.xcodeproj/project.pbxproj
@@ -26,6 +26,7 @@
 		64B441ED1ECEDEA600E66ACB /* QSRealmChangeManager.m in Sources */ = {isa = PBXBuildFile; fileRef = 64B441E81ECEDEA600E66ACB /* QSRealmChangeManager.m */; };
 		64B441EE1ECEDEA600E66ACB /* QSRecord.m in Sources */ = {isa = PBXBuildFile; fileRef = 64B441E91ECEDEA600E66ACB /* QSRecord.m */; };
 		64B441EF1ECEDEA600E66ACB /* QSSyncedEntity.m in Sources */ = {isa = PBXBuildFile; fileRef = 64B441EA1ECEDEA600E66ACB /* QSSyncedEntity.m */; };
+		64DFFAB71FEED0740072B8C3 /* QSKeyValueStore.h in Headers */ = {isa = PBXBuildFile; fileRef = 64DFFAB61FEED0730072B8C3 /* QSKeyValueStore.h */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -51,6 +52,7 @@
 		64B441E91ECEDEA600E66ACB /* QSRecord.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; name = QSRecord.m; path = ../../../SyncKit/Classes/Realm/QSRecord.m; sourceTree = "<group>"; };
 		64B441EA1ECEDEA600E66ACB /* QSSyncedEntity.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; name = QSSyncedEntity.m; path = ../../../SyncKit/Classes/Realm/QSSyncedEntity.m; sourceTree = "<group>"; };
 		64B441F51ECEE75700E66ACB /* Realm.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; path = Realm.framework; sourceTree = "<group>"; };
+		64DFFAB61FEED0730072B8C3 /* QSKeyValueStore.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = QSKeyValueStore.h; path = ../../../SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -98,6 +100,7 @@
 				64B441D01ECEDE4700E66ACB /* QSChangeManager.h */,
 				64B441D11ECEDE4700E66ACB /* QSCloudKitSynchronizer.h */,
 				64B441D21ECEDE4700E66ACB /* QSPrimaryKey.h */,
+				64DFFAB61FEED0730072B8C3 /* QSKeyValueStore.h */,
 				64B441D31ECEDE4700E66ACB /* QSSyncedEntityState.h */,
 				64B441D41ECEDE4700E66ACB /* SyncKitLog.h */,
 				64B441C81ECEDDF700E66ACB /* SyncKitRealm.h */,
@@ -134,6 +137,7 @@
 				64B441E31ECEDE9300E66ACB /* QSSyncedEntity.h in Headers */,
 				64B441D81ECEDE4700E66ACB /* QSSyncedEntityState.h in Headers */,
 				64AE808B1FD2FB50004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */,
+				64DFFAB71FEED0740072B8C3 /* QSKeyValueStore.h in Headers */,
 				64B441D91ECEDE4700E66ACB /* SyncKitLog.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/Example/SyncKitRealmOSX/SyncKitRealmOSX.xcodeproj/project.pbxproj b/Example/SyncKitRealmOSX/SyncKitRealmOSX.xcodeproj/project.pbxproj
index f4f1c826..ad440deb 100644
--- a/Example/SyncKitRealmOSX/SyncKitRealmOSX.xcodeproj/project.pbxproj
+++ b/Example/SyncKitRealmOSX/SyncKitRealmOSX.xcodeproj/project.pbxproj
@@ -26,6 +26,7 @@
 		644B0ECD1ED13C20003B0C51 /* SyncKitLog.h in Headers */ = {isa = PBXBuildFile; fileRef = 644B0EC31ED13C20003B0C51 /* SyncKitLog.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		64AE80931FD2FB6F004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 64AE80911FD2FB6F004BFEA4 /* QSCloudKitSynchronizer+Private.h */; };
 		64AE80941FD2FB6F004BFEA4 /* QSCloudKitSynchronizer+Private.m in Sources */ = {isa = PBXBuildFile; fileRef = 64AE80921FD2FB6F004BFEA4 /* QSCloudKitSynchronizer+Private.m */; };
+		64DFFAB91FEED0790072B8C3 /* QSKeyValueStore.h in Headers */ = {isa = PBXBuildFile; fileRef = 64DFFAB81FEED0790072B8C3 /* QSKeyValueStore.h */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -51,6 +52,7 @@
 		644B0ED01ED13CB8003B0C51 /* Realm.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Realm.framework; path = ../Realm.framework; sourceTree = "<group>"; };
 		64AE80911FD2FB6F004BFEA4 /* QSCloudKitSynchronizer+Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "QSCloudKitSynchronizer+Private.h"; path = "../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.h"; sourceTree = "<group>"; };
 		64AE80921FD2FB6F004BFEA4 /* QSCloudKitSynchronizer+Private.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = "QSCloudKitSynchronizer+Private.m"; path = "../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.m"; sourceTree = "<group>"; };
+		64DFFAB81FEED0790072B8C3 /* QSKeyValueStore.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = QSKeyValueStore.h; path = ../../../SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -92,6 +94,7 @@
 				644B0EBF1ED13C20003B0C51 /* QSChangeManager.h */,
 				644B0EC01ED13C20003B0C51 /* QSCloudKitSynchronizer.h */,
 				644B0EC11ED13C20003B0C51 /* QSPrimaryKey.h */,
+				64DFFAB81FEED0790072B8C3 /* QSKeyValueStore.h */,
 				644B0EC21ED13C20003B0C51 /* QSSyncedEntityState.h */,
 				644B0EC31ED13C20003B0C51 /* SyncKitLog.h */,
 				644B0EAE1ED13C0B003B0C51 /* QSCloudKitSynchronizer+Realm.m */,
@@ -126,6 +129,7 @@
 				644B0ECB1ED13C20003B0C51 /* QSPrimaryKey.h in Headers */,
 				644B0ECC1ED13C20003B0C51 /* QSSyncedEntityState.h in Headers */,
 				64AE80931FD2FB6F004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */,
+				64DFFAB91FEED0790072B8C3 /* QSKeyValueStore.h in Headers */,
 				644B0ECD1ED13C20003B0C51 /* SyncKitLog.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/Example/SyncKitRealmSwift/SyncKitRealmSwiftIOS/SyncKitRealmSwiftiOS.xcodeproj/project.pbxproj b/Example/SyncKitRealmSwift/SyncKitRealmSwiftIOS/SyncKitRealmSwiftiOS.xcodeproj/project.pbxproj
index 57c6bcc8..8aa7f9d4 100644
--- a/Example/SyncKitRealmSwift/SyncKitRealmSwiftIOS/SyncKitRealmSwiftiOS.xcodeproj/project.pbxproj
+++ b/Example/SyncKitRealmSwift/SyncKitRealmSwiftIOS/SyncKitRealmSwiftiOS.xcodeproj/project.pbxproj
@@ -22,6 +22,7 @@
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 		64AE80971FD2FBB9004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 64AE80951FD2FBB8004BFEA4 /* QSCloudKitSynchronizer+Private.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		64AE80981FD2FBB9004BFEA4 /* QSCloudKitSynchronizer+Private.m in Sources */ = {isa = PBXBuildFile; fileRef = 64AE80961FD2FBB8004BFEA4 /* QSCloudKitSynchronizer+Private.m */; };
+		64DFFABD1FEED0990072B8C3 /* QSKeyValueStore.h in Headers */ = {isa = PBXBuildFile; fileRef = 64DFFABC1FEED0990072B8C3 /* QSKeyValueStore.h */; settings = {ATTRIBUTES = (Public, ); }; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -44,6 +45,7 @@
 		644A06001F5978FC00F69505 /* RealmSwift.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; path = RealmSwift.framework; sourceTree = "<group>"; };
 		64AE80951FD2FBB8004BFEA4 /* QSCloudKitSynchronizer+Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "QSCloudKitSynchronizer+Private.h"; path = "../../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.h"; sourceTree = "<group>"; };
 		64AE80961FD2FBB8004BFEA4 /* QSCloudKitSynchronizer+Private.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = "QSCloudKitSynchronizer+Private.m"; path = "../../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.m"; sourceTree = "<group>"; };
+		64DFFABC1FEED0990072B8C3 /* QSKeyValueStore.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = QSKeyValueStore.h; path = ../../../../SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -90,6 +92,7 @@
 				644A05F21F59785A00F69505 /* QSCloudKitSynchronizer.h */,
 				644A05F31F59785A00F69505 /* QSCloudKitSynchronizer.m */,
 				644A05F41F59785A00F69505 /* QSPrimaryKey.h */,
+				64DFFABC1FEED0990072B8C3 /* QSKeyValueStore.h */,
 				644A05F51F59785A00F69505 /* QSSyncedEntityState.h */,
 				644A05F61F59785A00F69505 /* SyncKit.h */,
 				644A05F71F59785A00F69505 /* SyncKitLog.h */,
@@ -111,6 +114,7 @@
 				644A05FB1F59785A00F69505 /* QSPrimaryKey.h in Headers */,
 				644A05FE1F59785A00F69505 /* SyncKitLog.h in Headers */,
 				644A05E11F59782600F69505 /* SyncKitRealmSwift.h in Headers */,
+				64DFFABD1FEED0990072B8C3 /* QSKeyValueStore.h in Headers */,
 				644A05F91F59785A00F69505 /* QSCloudKitSynchronizer.h in Headers */,
 				64AE80971FD2FBB9004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */,
 			);
diff --git a/Example/SyncKitRealmSwift/SyncKitRealmSwiftOSX/SyncKitRealmSwiftOSX.xcodeproj/project.pbxproj b/Example/SyncKitRealmSwift/SyncKitRealmSwiftOSX/SyncKitRealmSwiftOSX.xcodeproj/project.pbxproj
index 70324c2a..6f91f86e 100644
--- a/Example/SyncKitRealmSwift/SyncKitRealmSwiftOSX/SyncKitRealmSwiftOSX.xcodeproj/project.pbxproj
+++ b/Example/SyncKitRealmSwift/SyncKitRealmSwiftOSX/SyncKitRealmSwiftOSX.xcodeproj/project.pbxproj
@@ -22,6 +22,7 @@
 		644A06301F597A6400F69505 /* SyncKitLog.h in Headers */ = {isa = PBXBuildFile; fileRef = 644A06241F597A6400F69505 /* SyncKitLog.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		64AE809B1FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 64AE80991FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		64AE809C1FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.m in Sources */ = {isa = PBXBuildFile; fileRef = 64AE809A1FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.m */; };
+		64DFFABB1FEED0930072B8C3 /* QSKeyValueStore.h in Headers */ = {isa = PBXBuildFile; fileRef = 64DFFABA1FEED0920072B8C3 /* QSKeyValueStore.h */; settings = {ATTRIBUTES = (Public, ); }; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -44,6 +45,7 @@
 		644A06321F597A7600F69505 /* RealmSwift.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; path = RealmSwift.framework; sourceTree = "<group>"; };
 		64AE80991FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "QSCloudKitSynchronizer+Private.h"; path = "../../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.h"; sourceTree = "<group>"; };
 		64AE809A1FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = "QSCloudKitSynchronizer+Private.m"; path = "../../../../SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer+Private.m"; sourceTree = "<group>"; };
+		64DFFABA1FEED0920072B8C3 /* QSKeyValueStore.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = QSKeyValueStore.h; path = ../../../../SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -88,6 +90,7 @@
 				64AE80991FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.h */,
 				64AE809A1FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.m */,
 				644A06211F597A6400F69505 /* QSPrimaryKey.h */,
+				64DFFABA1FEED0920072B8C3 /* QSKeyValueStore.h */,
 				644A06221F597A6400F69505 /* QSSyncedEntityState.h */,
 				644A06231F597A6400F69505 /* SyncKit.h */,
 				644A06241F597A6400F69505 /* SyncKitLog.h */,
@@ -111,6 +114,7 @@
 				644A062D1F597A6400F69505 /* QSPrimaryKey.h in Headers */,
 				644A06301F597A6400F69505 /* SyncKitLog.h in Headers */,
 				644A06131F597A1700F69505 /* SyncKitRealmSwift.h in Headers */,
+				64DFFABB1FEED0930072B8C3 /* QSKeyValueStore.h in Headers */,
 				64AE809B1FD2FD49004BFEA4 /* QSCloudKitSynchronizer+Private.h in Headers */,
 				644A062B1F597A6400F69505 /* QSCloudKitSynchronizer.h in Headers */,
 			);
diff --git a/Example/Tests/QSCloudKitSynchronizerTests.m b/Example/Tests/QSCloudKitSynchronizerTests.m
index c196fe14..05badbc4 100644
--- a/Example/Tests/QSCloudKitSynchronizerTests.m
+++ b/Example/Tests/QSCloudKitSynchronizerTests.m
@@ -13,6 +13,7 @@
 #import "QSMockChangeManager.h"
 #import "QSMockDatabase.h"
 #import "QSObject.h"
+#import "QSMockKeyValueStore.h"
 
 @interface QSCloudKitSynchronizerTests : XCTestCase
 
@@ -21,6 +22,7 @@ @interface QSCloudKitSynchronizerTests : XCTestCase
 @property (nonatomic, strong) QSMockChangeManager *mockChangeManager;
 @property (nonatomic, strong) CKRecordZoneID *recordZoneID;
 @property (nonatomic, strong) id mockContainer;
+@property (nonatomic, strong) QSMockKeyValueStore *mockKeyValueStore;
 
 @end
 
@@ -30,6 +32,8 @@ - (void)setUp {
     [super setUp];
     // Put setup code here. This method is called before the invocation of each test method in the class.
     
+    self.mockKeyValueStore = [[QSMockKeyValueStore alloc] init];
+    
     //Pass our custom database
     self.mockDatabase = [QSMockDatabase new];
     
@@ -41,11 +45,24 @@ - (void)setUp {
     
     self.recordZoneID = [[CKRecordZoneID alloc] initWithZoneName:@"zone" ownerName:@"owner"];
     
-    self.synchronizer = [[QSCloudKitSynchronizer alloc] initWithContainerIdentifier:@"any" recordZoneID:self.recordZoneID changeManager:self.mockChangeManager];
+    self.synchronizer = [self createSynchronizer];
+}
+
+- (QSCloudKitSynchronizer *)createSynchronizer
+{
+    return [[QSCloudKitSynchronizer alloc] initWithContainerIdentifier:@"any" recordZoneID:self.recordZoneID changeManager:self.mockChangeManager keyValueStore:self.mockKeyValueStore];
 }
 
 - (void)tearDown {
     // Put teardown code here. This method is called after the invocation of each test method in the class.
+    [self.mockKeyValueStore clear];
+    self.synchronizer = nil;
+    self.recordZoneID = nil;
+    self.mockChangeManager = nil;
+    self.mockContainer = nil;
+    self.mockDatabase = nil;
+    self.mockKeyValueStore = nil;
+    
     [super tearDown];
 }
 
@@ -154,6 +171,52 @@ - (void)testSynchronize_objectsToUploadAndDeleteAndFetch_UpdatesAll
     XCTAssertNotNil(fifthObject);
 }
 
+- (void)testSynchronize_errorInFetchRecordZone_customZoneNotCreated_createsZone
+{
+    XCTestExpectation *expectation = [self expectationWithDescription:@"Sync finished"];
+    
+    NSError *error = [NSError errorWithDomain:@"error" code:CKErrorUserDeletedZone userInfo:nil];
+    self.mockDatabase.fetchRecordZoneError = error;
+    
+    __block NSError *receivedError = nil;
+    
+    [self.synchronizer synchronizeWithCompletion:^(NSError *error) {
+        receivedError = error;
+        [expectation fulfill];
+    }];
+    
+    [self waitForExpectationsWithTimeout:1 handler:nil];
+    
+    XCTAssertNil(receivedError);
+}
+
+- (void)testSynchronize_errorInFetchRecordZone_customZoneCreated_endsWithError
+{
+    // Make sure record zone is created
+    XCTestExpectation *expectation = [self expectationWithDescription:@"Sync finished"];
+    [self.synchronizer synchronizeWithCompletion:^(NSError *error) {
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithTimeout:1 handler:nil];
+    
+    // New synchronizer, will try to fetch record zone
+    self.synchronizer = [self createSynchronizer];
+    NSError *error = [NSError errorWithDomain:@"error" code:CKErrorUserDeletedZone userInfo:nil];
+    self.mockDatabase.fetchRecordZoneError = error;
+    
+    __block NSError *receivedError = nil;
+    XCTestExpectation *expectation2 = [self expectationWithDescription:@"Sync finished"];
+    
+    [self.synchronizer synchronizeWithCompletion:^(NSError *error) {
+        receivedError = error;
+        [expectation2 fulfill];
+    }];
+    
+    [self waitForExpectationsWithTimeout:1 handler:nil];
+    
+    XCTAssertEqual(receivedError, error);
+}
+
 - (void)testSynchronize_errorInFetch_endsWithError
 {
     XCTestExpectation *expectation = [self expectationWithDescription:@"Sync finished"];
diff --git a/Example/Tests/QSMockDatabase.h b/Example/Tests/QSMockDatabase.h
index b045436c..29957b5d 100644
--- a/Example/Tests/QSMockDatabase.h
+++ b/Example/Tests/QSMockDatabase.h
@@ -18,6 +18,7 @@
 @property (nonatomic, strong, nullable) NSArray *readyToFetchRecords;
 @property (nonatomic, strong, nullable) NSArray *toDeleteRecordIDs;
 
+@property (nonatomic, strong, nullable) NSError *fetchRecordZoneError;
 @property (nonatomic, strong, nullable) NSError *fetchError;
 @property (nonatomic, strong, nullable) NSError *uploadError;
 
diff --git a/Example/Tests/QSMockDatabase.m b/Example/Tests/QSMockDatabase.m
index a6faa38a..9c7105d5 100644
--- a/Example/Tests/QSMockDatabase.m
+++ b/Example/Tests/QSMockDatabase.m
@@ -119,8 +119,12 @@ - (void)handleModifyRecordsOperation:(CKModifyRecordsOperation *)operation
 
 - (void)fetchRecordZoneWithID:(CKRecordZoneID *)zoneID completionHandler:(void (^)(CKRecordZone * _Nullable, NSError * _Nullable))completionHandler
 {
-    CKRecordZone *zone = [[CKRecordZone alloc] initWithZoneID:zoneID];
-    completionHandler(zone, nil);
+    if (self.fetchRecordZoneError) {
+        completionHandler(nil, self.fetchRecordZoneError);
+    } else {
+        CKRecordZone *zone = [[CKRecordZone alloc] initWithZoneID:zoneID];
+        completionHandler(zone, nil);
+    }
 }
 
 - (void)saveRecordZone:(CKRecordZone *)zone completionHandler:(void (^)(CKRecordZone * _Nullable, NSError * _Nullable))completionHandler
diff --git a/Example/Tests/QSMockKeyValueStore.h b/Example/Tests/QSMockKeyValueStore.h
new file mode 100644
index 00000000..d51d7dee
--- /dev/null
+++ b/Example/Tests/QSMockKeyValueStore.h
@@ -0,0 +1,16 @@
+//
+//  QSMockKeyValueStore.h
+//  SyncKitCoreDataExampleTests
+//
+//  Created by Manuel Entrena on 22/12/2017.
+//  Copyright © 2017 Manuel. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+#import <SyncKit/QSKeyValueStore.h>
+
+@interface QSMockKeyValueStore : NSObject <QSKeyValueStore>
+
+- (void)clear;
+
+@end
diff --git a/Example/Tests/QSMockKeyValueStore.m b/Example/Tests/QSMockKeyValueStore.m
new file mode 100644
index 00000000..7926f899
--- /dev/null
+++ b/Example/Tests/QSMockKeyValueStore.m
@@ -0,0 +1,58 @@
+//
+//  QSMockKeyValueStore.m
+//  SyncKitCoreDataExampleTests
+//
+//  Created by Manuel Entrena on 22/12/2017.
+//  Copyright © 2017 Manuel. All rights reserved.
+//
+
+#import "QSMockKeyValueStore.h"
+
+@interface QSMockKeyValueStore ()
+
+@property (nonatomic, strong) NSMutableDictionary *dictionary;
+
+@end
+
+@implementation QSMockKeyValueStore
+
+- (instancetype)init
+{
+    self = [super init];
+    if (self) {
+        self.dictionary = [NSMutableDictionary dictionary];
+    }
+    return self;
+}
+
+- (id)objectForKey:(NSString *)defaultName
+{
+    return [self.dictionary objectForKey:defaultName];
+}
+
+- (void)setObject:(id)value forKey:(NSString *)defaultName
+{
+    [self.dictionary setObject:value forKey:defaultName];
+}
+
+- (BOOL)boolForKey:(NSString *)defaultName
+{
+    return [[self.dictionary objectForKey:defaultName] boolValue];
+}
+
+- (void)setBool:(BOOL)value forKey:(NSString *)defaultName
+{
+    [self.dictionary setObject:@(value) forKey:defaultName];
+}
+
+- (void)removeObjectForKey:(NSString *)defaultName
+{
+    [self.dictionary removeObjectForKey:defaultName];
+}
+
+- (void)clear
+{
+    [self.dictionary removeAllObjects];
+}
+
+@end
diff --git a/SyncKit.podspec b/SyncKit.podspec
index 2d951d84..d5ae5387 100644
--- a/SyncKit.podspec
+++ b/SyncKit.podspec
@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'SyncKit'
-  s.version          = '0.5.6'
+  s.version          = '0.5.7'
   s.summary          = 'CloudKit synchronization for your Core Data or Realm model.'
 
   s.description      = <<-DESC
diff --git a/SyncKit/Classes/CoreData/QSCloudKitSynchronizer+CoreData.m b/SyncKit/Classes/CoreData/QSCloudKitSynchronizer+CoreData.m
index 273a8e2b..6f11073f 100644
--- a/SyncKit/Classes/CoreData/QSCloudKitSynchronizer+CoreData.m
+++ b/SyncKit/Classes/CoreData/QSCloudKitSynchronizer+CoreData.m
@@ -63,7 +63,8 @@ + (QSCloudKitSynchronizer *)cloudKitSynchronizerWithContainerName:(NSString *)co
 {
     QSCoreDataStack *stack = [[QSCoreDataStack alloc] initWithStoreType:NSSQLiteStoreType model:[QSCoreDataChangeManager persistenceModel] storePath:[self storePathWithAppGroup:suiteName]];
     QSCoreDataChangeManager *changeManager = [[QSCoreDataChangeManager alloc] initWithPersistenceStack:stack targetContext:context recordZoneID:[self defaultCustomZoneID] delegate:delegate];
-    QSCloudKitSynchronizer *synchronizer = [[QSCloudKitSynchronizer alloc] initWithContainerIdentifier:containerName recordZoneID:[self defaultCustomZoneID] changeManager:changeManager suiteName:suiteName];
+    NSUserDefaults *suiteUserDefaults = [[NSUserDefaults alloc] initWithSuiteName:suiteName];
+    QSCloudKitSynchronizer *synchronizer = [[QSCloudKitSynchronizer alloc] initWithContainerIdentifier:containerName recordZoneID:[self defaultCustomZoneID] changeManager:changeManager keyValueStore:suiteUserDefaults];
     return synchronizer;
 }
 
diff --git a/SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer.h b/SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer.h
index 749ecb09..9f1b2d4e 100644
--- a/SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer.h
+++ b/SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer.h
@@ -8,6 +8,7 @@
 
 #import <Foundation/Foundation.h>
 #import "QSChangeManager.h"
+#import "QSKeyValueStore.h"
 
 @class CKRecordZoneID;
 
@@ -62,11 +63,6 @@ typedef NS_ENUM(NSInteger, QSCloudKitSynchronizeMode)
  */
 @property (nonatomic, assign) QSCloudKitSynchronizeMode syncMode;
 
-/*
- *  App Group identifier, if SyncKit is to be configured to store its tracking data in a shared container for that app group.
- */
-@property (nonatomic, readonly) NSString *suiteName;
-
 + (NSArray<NSString *> *)synchronizerMetadataKeys;
 
 
@@ -88,11 +84,11 @@ typedef NS_ENUM(NSInteger, QSCloudKitSynchronizeMode)
  *  @param containerIdentifier Identifier of the iCloud container to be used. The application must have the right entitlements to be able to access this container.
  *  @param zoneID              Identifier of the`CKRecordZone` that will contain all data.
  *  @param changeManager       Object conforming to `QSChangeManager`, to interact with local model.
- *  @param suiteName           App Group identifier, to configure SyncKit to store its data in the shared container.
+ *  @param keyValueStore       Object conforming to QSKeyValueStore (NSUserDefaults, for example)
  *
  *  @return Initialized synchronizer or `nil` if no iCloud container can be found with the provided identifier.
  */
-- (instancetype)initWithContainerIdentifier:(NSString *)containerIdentifier recordZoneID:(CKRecordZoneID *)zoneID changeManager:(id<QSChangeManager>)changeManager suiteName:(NSString *)suiteName;
+- (instancetype)initWithContainerIdentifier:(NSString *)containerIdentifier recordZoneID:(CKRecordZoneID *)zoneID changeManager:(id<QSChangeManager>)changeManager keyValueStore:(id<QSKeyValueStore>)keyValueStore;
 
 /**
  *  Performs synchronization with CloudKit.
diff --git a/SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer.m b/SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer.m
index 483690b9..8449eaff 100644
--- a/SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer.m
+++ b/SyncKit/Classes/QSSynchronizer/QSCloudKitSynchronizer.m
@@ -36,8 +36,8 @@ @interface QSCloudKitSynchronizer ()
 @property (nonatomic, strong) CKDatabase *database;
 @property (nonatomic, strong) CKRecordZoneID *customZoneID;
 @property (nonatomic, strong) CKRecordZone *customZone;
-@property (nonatomic, strong, readwrite) NSString *suiteName;
 @property (atomic, readwrite, assign, getter=isSyncing) BOOL syncing;
+@property (nonatomic, assign, getter=isCustomZoneCreated) BOOL customZoneCreated;
 
 @property (nonatomic, assign) NSInteger batchSize;
 
@@ -51,7 +51,7 @@ @interface QSCloudKitSynchronizer ()
 
 @property (nonatomic, strong) dispatch_queue_t dispatchQueue;
 
-@property (nonatomic, strong) NSUserDefaults *userDefaults;
+@property (nonatomic, strong) id<QSKeyValueStore> keyValueStore;
 
 @end
 
@@ -59,18 +59,17 @@ @implementation QSCloudKitSynchronizer
 
 - (instancetype)initWithContainerIdentifier:(NSString *)containerIdentifier recordZoneID:(CKRecordZoneID *)zoneID changeManager:(id<QSChangeManager>)changeManager
 {
-    return [self initWithContainerIdentifier:containerIdentifier recordZoneID:zoneID changeManager:changeManager suiteName:nil];
+    return [self initWithContainerIdentifier:containerIdentifier recordZoneID:zoneID changeManager:changeManager keyValueStore:[NSUserDefaults standardUserDefaults]];
 }
 
-- (instancetype)initWithContainerIdentifier:(NSString *)containerIdentifier recordZoneID:(CKRecordZoneID *)zoneID changeManager:(id<QSChangeManager>)changeManager suiteName:(NSString *)suiteName
+- (instancetype)initWithContainerIdentifier:(NSString *)containerIdentifier recordZoneID:(CKRecordZoneID *)zoneID changeManager:(id<QSChangeManager>)changeManager keyValueStore:(id<QSKeyValueStore>)keyValueStore;
 {
     self = [super init];
     if (self) {
         self.containerIdentifier = containerIdentifier;
         self.customZoneID = zoneID;
         self.changeManager = changeManager;
-        self.suiteName = suiteName;
-        self.userDefaults = [[NSUserDefaults alloc] initWithSuiteName:self.suiteName];
+        self.keyValueStore = keyValueStore;
         
         self.batchSize = QSDefaultBatchSize;
         self.compatibilityVersion = 0;
@@ -96,11 +95,11 @@ - (NSString *)deviceIdentifier
 {
     if (!_deviceIdentifier) {
         
-        _deviceIdentifier = [self.userDefaults objectForKey:[self userDefaultsKeyForKey:QSCloudKitDeviceUUIDKey]];
+        _deviceIdentifier = [self.keyValueStore objectForKey:[self userDefaultsKeyForKey:QSCloudKitDeviceUUIDKey]];
         if (!_deviceIdentifier) {
             NSUUID *UUID = [NSUUID UUID];
             _deviceIdentifier = [UUID UUIDString];
-            [self.userDefaults setObject:_deviceIdentifier forKey:[self userDefaultsKeyForKey:QSCloudKitDeviceUUIDKey]];
+            [self.keyValueStore setObject:_deviceIdentifier forKey:[self userDefaultsKeyForKey:QSCloudKitDeviceUUIDKey]];
         }
     }
     return _deviceIdentifier;
@@ -114,19 +113,21 @@ - (void)setupCustomZoneWithCompletion:(void(^)(NSError *error))completionBlock
             if (zone) {
                 DLog(@"QSCloudKitSynchronizer >> Fetched custom record zone");
                 self.customZone = zone;
-                [self.userDefaults setBool:YES forKey:[self userDefaultsKeyForKey:QSCloudKitCustomZoneCreatedKey]];
+                self.customZoneCreated = YES;
                 callBlockIfNotNil(completionBlock, error);
-            } else if (error.code  == CKErrorZoneNotFound &&
-                       [self.userDefaults boolForKey:[self userDefaultsKeyForKey:QSCloudKitCustomZoneCreatedKey]] == NO) {
+            } else if ((error.code  == CKErrorZoneNotFound || error.code == CKErrorUserDeletedZone) &&
+                       self.isCustomZoneCreated == NO) {
+                
                 self.customZone = [[CKRecordZone alloc] initWithZoneID:self.customZoneID];
                 [self.database saveRecordZone:self.customZone completionHandler:^(CKRecordZone * _Nullable zone, NSError * _Nullable error) {
                     if (!error && zone) {
                         DLog(@"QSCloudKitSynchronizer >> Created custom record zone");
                         self.customZone = zone;
-                        [self.userDefaults setBool:YES forKey:[self userDefaultsKeyForKey:QSCloudKitCustomZoneCreatedKey]];
+                        self.customZoneCreated = YES;
                     }
                     callBlockIfNotNil(completionBlock, error);
                 }];
+                
             } else {
                 callBlockIfNotNil(completionBlock, error);
             }
@@ -137,6 +138,16 @@ - (void)setupCustomZoneWithCompletion:(void(^)(NSError *error))completionBlock
     }
 }
 
+- (BOOL)isCustomZoneCreated
+{
+    return [self.keyValueStore boolForKey:[self userDefaultsKeyForKey:QSCloudKitCustomZoneCreatedKey]];
+}
+
+- (void)setCustomZoneCreated:(BOOL)created
+{
+    [self.keyValueStore setBool:created forKey:[self userDefaultsKeyForKey:QSCloudKitCustomZoneCreatedKey]];
+}
+
 #pragma mark - Public
 
 + (NSArray<NSString *> *)synchronizerMetadataKeys
@@ -195,10 +206,12 @@ - (void)cancelSynchronization
 
 - (void)eraseLocal
 {
-    [self.userDefaults removeObjectForKey:[self userDefaultsKeyForKey:QSCloudKitFetchChangesServerTokenKey]];
-    [self.userDefaults removeObjectForKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
-    [self.userDefaults removeObjectForKey:[self userDefaultsKeyForKey:QSCloudKitCustomZoneCreatedKey]];
-    [self.userDefaults removeObjectForKey:[self userDefaultsKeyForKey:QSCloudKitDeviceUUIDKey]];
+    [self.keyValueStore removeObjectForKey:[self userDefaultsKeyForKey:QSCloudKitFetchChangesServerTokenKey]];
+    [self.keyValueStore removeObjectForKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
+    self.customZoneCreated = NO;
+    [self.keyValueStore removeObjectForKey:[self userDefaultsKeyForKey:QSCloudKitDeviceUUIDKey]];
+    
+    self.customZone = nil;
     
     [self.changeManager deleteChangeTracking];
 }
@@ -335,7 +348,7 @@ - (void)finishSynchronizationWithError:(NSError *)error
 
 - (void)restoreServerChangeToken
 {
-    NSData *encodedToken = [self.userDefaults objectForKey:[self userDefaultsKeyForKey:QSCloudKitFetchChangesServerTokenKey]];
+    NSData *encodedToken = [self.keyValueStore objectForKey:[self userDefaultsKeyForKey:QSCloudKitFetchChangesServerTokenKey]];
     if (encodedToken) {
         self.serverChangeToken = [NSKeyedUnarchiver unarchiveObjectWithData:encodedToken];
     }
@@ -344,7 +357,7 @@ - (void)restoreServerChangeToken
 - (void)saveServerChangeToken:(CKServerChangeToken *)token
 {
     NSData *encodedToken = [NSKeyedArchiver archivedDataWithRootObject:token];
-    [self.userDefaults setObject:encodedToken forKey:[self userDefaultsKeyForKey:QSCloudKitFetchChangesServerTokenKey]];
+    [self.keyValueStore setObject:encodedToken forKey:[self userDefaultsKeyForKey:QSCloudKitFetchChangesServerTokenKey]];
 }
 
 - (void)uploadChangesWithCompletion:(void(^)(NSError *error))completion
@@ -698,7 +711,7 @@ - (void)subscribeForChangesInRecordZoneWithCompletion:(void(^)(NSError *error))c
                 
                 if (existingSubscriptionIdentifier) {
                     // Found existing subscription
-                    [self.userDefaults setObject:existingSubscriptionIdentifier forKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
+                    [self.keyValueStore setObject:existingSubscriptionIdentifier forKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
                     callBlockIfNotNil(completion, nil);
                 } else {
                     // Create new one
@@ -715,7 +728,7 @@ - (void)subscribeForChangesInRecordZoneWithCompletion:(void(^)(NSError *error))c
                     
                     [self.database saveSubscription:subscription completionHandler:^(CKSubscription * _Nullable subscription, NSError * _Nullable error) {
                         if (!error) {
-                            [self.userDefaults setObject:subscription.subscriptionID forKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
+                            [self.keyValueStore setObject:subscription.subscriptionID forKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
                         }
                         
                         callBlockIfNotNil(completion, error);
@@ -730,7 +743,7 @@ - (void)subscribeForChangesInRecordZoneWithCompletion:(void(^)(NSError *error))c
 
 - (void)cancelSubscriptionForChangesInRecordZoneWithCompletion:(void(^)(NSError *error))completion
 {
-    NSString *subscriptionID = [self.userDefaults objectForKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
+    NSString *subscriptionID = [self.keyValueStore objectForKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
     
     if (subscriptionID) {
         [self cancelSubscriptionWithID:subscriptionID withCompletion:completion];
@@ -762,14 +775,14 @@ - (void)cancelSubscriptionForChangesInRecordZoneWithCompletion:(void(^)(NSError
 - (void)cancelSubscriptionWithID:(NSString *)subscriptionID withCompletion:(void(^)(NSError *error))completion
 {
     [self.database deleteSubscriptionWithID:subscriptionID completionHandler:^(NSString * _Nullable subscriptionID, NSError * _Nullable error) {
-        [self.userDefaults removeObjectForKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
+        [self.keyValueStore removeObjectForKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
         callBlockIfNotNil(completion, error);
     }];
 }
 
 - (NSString *)subscriptionID
 {
-    return [self.userDefaults objectForKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
+    return [self.keyValueStore objectForKey:[self userDefaultsKeyForKey:QSSubscriptionIdentifierKey]];
 }
 
 #endif
diff --git a/SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h b/SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h
new file mode 100644
index 00000000..c08c3689
--- /dev/null
+++ b/SyncKit/Classes/QSSynchronizer/QSKeyValueStore.h
@@ -0,0 +1,21 @@
+//
+//  QSKeyValueStore.h
+//  Pods
+//
+//  Created by Manuel Entrena on 22/12/2017.
+//
+
+#import <Foundation/Foundation.h>
+
+@protocol QSKeyValueStore <NSObject>
+
+- (id)objectForKey:(NSString *)defaultName;
+- (void)setObject:(id)value forKey:(NSString *)defaultName;
+- (BOOL)boolForKey:(NSString *)defaultName;
+- (void)setBool:(BOOL)value forKey:(NSString *)defaultName;
+- (void)removeObjectForKey:(NSString *)defaultName;
+
+@end
+
+@interface NSUserDefaults (QSKeyValueStore) <QSKeyValueStore>
+@end
diff --git a/SyncKit/Classes/Realm/QSCloudKitSynchronizer+Realm.m b/SyncKit/Classes/Realm/QSCloudKitSynchronizer+Realm.m
index d25cd36b..24b9e4a2 100644
--- a/SyncKit/Classes/Realm/QSCloudKitSynchronizer+Realm.m
+++ b/SyncKit/Classes/Realm/QSCloudKitSynchronizer+Realm.m
@@ -72,7 +72,8 @@ + (QSCloudKitSynchronizer *)cloudKitSynchronizerWithContainerName:(NSString *)co
 {
     [self ensurePathAvailableWithSuiteName:suiteName];
     QSRealmChangeManager *changeManager = [[QSRealmChangeManager alloc] initWithPersistenceRealmConfiguration:[self persistenceConfigurationWithSuiteName:suiteName] targetRealmConfiguration:targetRealmConfiguration recordZoneID:[self defaultCustomZoneID]];
-    QSCloudKitSynchronizer *synchronizer = [[QSCloudKitSynchronizer alloc] initWithContainerIdentifier:containerName recordZoneID:[self defaultCustomZoneID] changeManager:changeManager suiteName:suiteName];
+    NSUserDefaults *suiteUserDefaults = [[NSUserDefaults alloc] initWithSuiteName:suiteName];
+    QSCloudKitSynchronizer *synchronizer = [[QSCloudKitSynchronizer alloc] initWithContainerIdentifier:containerName recordZoneID:[self defaultCustomZoneID] changeManager:changeManager keyValueStore:suiteUserDefaults];
     return synchronizer;
 }
 
diff --git a/SyncKit/Classes/RealmSwift/QSCloudKitSynchronizer+RealmSwift.swift b/SyncKit/Classes/RealmSwift/QSCloudKitSynchronizer+RealmSwift.swift
index 4ed91a7a..fb0264aa 100644
--- a/SyncKit/Classes/RealmSwift/QSCloudKitSynchronizer+RealmSwift.swift
+++ b/SyncKit/Classes/RealmSwift/QSCloudKitSynchronizer+RealmSwift.swift
@@ -62,7 +62,8 @@ extension QSCloudKitSynchronizer {
         
         ensurePathAvailable(suiteName: suiteName)
         let changeManager = RealmSwiftChangeManager(persistenceRealmConfiguration: persistenceConfiguration(suiteName: suiteName), targetRealmConfiguration: configuration, recordZoneID: defaultCustomZoneID())
-        return QSCloudKitSynchronizer(containerIdentifier: containerName, recordZoneID: defaultCustomZoneID(), changeManager: changeManager, suiteName: suiteName)
+        let suiteUserDefaults = UserDefaults(suiteName: suiteName)
+        return QSCloudKitSynchronizer(containerIdentifier: containerName, recordZoneID: defaultCustomZoneID(), changeManager: changeManager, keyValueStore: suiteUserDefaults)
     }
     
 }