diff --git a/rtl/unix/clocale.pp b/rtl/unix/clocale.pp
index 0e5f451578..38360a3933 100644
--- a/rtl/unix/clocale.pp
+++ b/rtl/unix/clocale.pp
@@ -260,7 +260,10 @@ begin
   OrgFormatSettings.LongTimeFormat:=longtimeformat;
 {$endif}
 
-  LongTimeFormat := TransformFormatStr(LongTimeFormat);
+  if (LongTimeFormat='') then
+    LongTimeFormat:=ShortTimeFormat
+  else
+    LongTimeFormat := TransformFormatStr(LongTimeFormat);
 
   {$Ifdef BSD}
      plocale:=localeconv;