diff --git a/panda/src/express/mutexWin32Impl.I b/panda/src/express/mutexWin32Impl.I
index 40d293e7c2..6b321f458d 100644
--- a/panda/src/express/mutexWin32Impl.I
+++ b/panda/src/express/mutexWin32Impl.I
@@ -54,7 +54,7 @@ lock() {
 ////////////////////////////////////////////////////////////////////
 INLINE bool MutexWin32Impl::
 try_lock() {
-  return TryEnterCriticalSection(&_lock);
+  return (TryEnterCriticalSection(&_lock) != 0);
 }
 
 ////////////////////////////////////////////////////////////////////