diff --git a/appveyor.yml b/appveyor.yml
index 873f4fe2..b88ade97 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -11,7 +11,7 @@ build_script:
 
     cd cmakebuild
 
-    cmake .. -DCMAKE_GENERATOR_PLATFORM=%platform%
+    cmake .. -DCMAKE_GENERATOR_PLATFORM=$env:Platform
 
     msbuild PACKAGE.vcxproj /p:Configuration=Release /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
 artifacts: