diff --git a/rtl/unix/timezone.inc b/rtl/unix/timezone.inc
index 24f9aa07fa..d1d4fe24e3 100644
--- a/rtl/unix/timezone.inc
+++ b/rtl/unix/timezone.inc
@@ -210,7 +210,7 @@ var
   NewTZInfoEx: TTZInfoEx;
 begin
   LockTZInfo;
-  if GetLocalTimezone(fptime,false,NewTZInfo,NewTZInfoEx) then
+  if GetLocalTimezone(fptime,true,NewTZInfo,NewTZInfoEx) then
     SetTZInfo(NewTZInfo,NewTZInfoEx);
   UnlockTZInfo;
 end;