diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 3b810ce..15d5587 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -26,7 +26,7 @@ jobs:
 
       - name: configure
         env:
-          CPM_SOURCE_CACHE: ${GITHUB_WORKSPACE}/cpm_modules
+          CPM_SOURCE_CACHE: ${{ env.GITHUB_WORKSPACE }}/cpm_modules
         run: cmake -Stest -Bbuild
 
       - name: build