diff --git a/srtcore/buffer_rcv.h b/srtcore/buffer_rcv.h
index 4ee791ec1..41324d6d4 100644
--- a/srtcore/buffer_rcv.h
+++ b/srtcore/buffer_rcv.h
@@ -14,7 +14,6 @@
 #include "buffer_tools.h" // AvgBufSize
 #include "common.h"
 #include "queue.h"
-#include "sync.h"
 #include "tsbpd_time.h"
 
 namespace srt
diff --git a/srtcore/buffer_tools.cpp b/srtcore/buffer_tools.cpp
index b0b2b925d..1cdc72d58 100644
--- a/srtcore/buffer_tools.cpp
+++ b/srtcore/buffer_tools.cpp
@@ -54,7 +54,6 @@ modified by
 #include "buffer_tools.h"
 #include "packet.h"
 #include "logger_defs.h"
-#include "sync.h"
 #include "utilities.h"
 
 namespace srt {
diff --git a/srtcore/buffer_tools.h b/srtcore/buffer_tools.h
index e081e6651..a6d81a356 100644
--- a/srtcore/buffer_tools.h
+++ b/srtcore/buffer_tools.h
@@ -53,7 +53,6 @@ modified by
 #ifndef INC_SRT_BUFFER_TOOLS_H
 #define INC_SRT_BUFFER_TOOLS_H
 
-#include "sync.h"
 #include "common.h"
 
 namespace srt {
diff --git a/srtcore/sync.h b/srtcore/sync.h
index 5d62536eb..b3122333a 100644
--- a/srtcore/sync.h
+++ b/srtcore/sync.h
@@ -11,6 +11,8 @@
 #ifndef INC_SRT_SYNC_H
 #define INC_SRT_SYNC_H
 
+#include "platform_sys.h"
+
 #include <cstdlib>
 #include <limits>
 #ifdef ENABLE_STDCXX_SYNC