diff --git a/Source/NSThread.m b/Source/NSThread.m
index 695426084..db9377b6d 100644
--- a/Source/NSThread.m
+++ b/Source/NSThread.m
@@ -977,6 +977,7 @@ static void *nsthreadLauncher(void* thread)
   if (event != INVALID_HANDLE_VALUE)
     {
       CloseHandle(event);
+      event = INVALID_HANDLE_VALUE;
     }
 #else
   if (inputFd >= 0)