diff --git a/.appveyor.yml b/.appveyor.yml
index 622ad58..4498272 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -55,8 +55,7 @@ install:
     ) ELSE (
       ( CD Nim ) &
       ( git rev-parse HEAD > ..\\cur_ver.txt ) &
-      ( fc ver.txt ..\\cur_ver.txt > nul ) &
-      ( IF NOT ERRORLEVEL == 0 SET NEED_REBUILD=1 ) &
+      ( fc ver.txt ..\\cur_ver.txt || SET NEED_REBUILD=1 ) &
       ( cd .. )
     )