diff --git a/build.bat b/build.bat
index 736af51..361f821 100644
--- a/build.bat
+++ b/build.bat
@@ -111,7 +111,7 @@ set dev=""
 for /f "tokens=1,2,* " %%i in ('reg QUERY "HKEY_CLASSES_ROOT\CLSID\{2E1517DA-87BF-4443-984A-D2BF18F5A908}\LocalServer32" /ve') do set dev=%%k
 echo dev=%dev%
 
-if %dev%=="" (
+if "%dev%"=="" (
 echo "Can not find Visual-Studio installing path"
 goto end
 )