diff --git a/appveyor.yml b/appveyor.yml
index c3a62ba..5b000a9 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -9,8 +9,8 @@ install:
 - cmd: git submodule -q update --init
 before_build:
 - ps: Invoke-WebRequest "https://downloads.vigem.org/other/nefarius/vpatch/vpatch.exe" -OutFile vpatch.exe
-- cmd: vpatch.exe --stamp-version "$env:APPVEYOR_BUILD_VERSION" --target-file ".\sys\ViGEmBus.vcxproj" --vcxproj.inf-time-stamp
-- cmd: vpatch.exe --stamp-version "$env:APPVEYOR_BUILD_VERSION" --target-file ".\sys\ViGEmBus.rc" --resource.file-version --resource.product-version
+- cmd: vpatch.exe --stamp-version "%APPVEYOR_BUILD_VERSION%" --target-file ".\sys\ViGEmBus.vcxproj" --vcxproj.inf-time-stamp
+- cmd: vpatch.exe --stamp-version "%APPVEYOR_BUILD_VERSION%" --target-file ".\sys\ViGEmBus.rc" --resource.file-version --resource.product-version
 build:
   project: $(APPVEYOR_BUILD_FOLDER)\$(APPVEYOR_PROJECT_NAME).sln
 after_build: