diff --git a/.github/workflows/d3d11-test-msys2.yml b/.github/workflows/d3d11-test-msys2.yml
index 71c6e26..00419f5 100644
--- a/.github/workflows/d3d11-test-msys2.yml
+++ b/.github/workflows/d3d11-test-msys2.yml
@@ -31,6 +31,7 @@ jobs:
     steps:
     - name: Get current date as package key
       id: cache_key
+      shell: bash
       run: echo "key=$(date +'%W')" >> $GITHUB_OUTPUT
 
     - name: Checkout repository