diff --git a/src/main/java/com/google/devtools/build/lib/sandbox/NamespaceSandboxRunner.java b/src/main/java/com/google/devtools/build/lib/sandbox/NamespaceSandboxRunner.java
index e16ac70e1c2c08..74649e615d7207 100644
--- a/src/main/java/com/google/devtools/build/lib/sandbox/NamespaceSandboxRunner.java
+++ b/src/main/java/com/google/devtools/build/lib/sandbox/NamespaceSandboxRunner.java
@@ -163,7 +163,9 @@ private void copyOutputs(Collection<? extends ActionInput> outputs) throws IOExc
       Path source = sandboxExecRoot.getRelative(output.getExecPathString());
       Path target = execRoot.getRelative(output.getExecPathString());
       FileSystemUtils.createDirectoryAndParents(target.getParentDirectory());
-      Files.move(source.getPathFile(), target.getPathFile());
+      if (source.isFile()) {
+        Files.move(new File(source.getPathString()), new File(target.getPathString()));
+      }
     }
   }