diff --git a/Source/NSObject.m b/Source/NSObject.m
index fa5a75ed8..43dab8ffd 100644
--- a/Source/NSObject.m
+++ b/Source/NSObject.m
@@ -2104,7 +2104,7 @@ static id gs_weak_load(id obj)
 
   if (aSelector == 0)
     {
-      if (GSPrivateDefaultsFlag(GSMacOSXCompatible))
+      if (!GSPrivateDefaultsFlag(GSMacOSXCompatible))
 	{
 	  [NSException raise: NSInvalidArgumentException
 		    format: @"%@ null selector given",