diff --git a/.github/workflows/mocha.yml b/.github/workflows/mocha.yml
index 4625ff6867..cc89f9a451 100644
--- a/.github/workflows/mocha.yml
+++ b/.github/workflows/mocha.yml
@@ -116,9 +116,9 @@ jobs:
         uses: actions/cache@v2
         with:
           path: GrowlInstaller
-          key: '${{ runner.os }}-growl-installer'
+          key: ${{ runner.os }}-growl-installer-${{ hashFiles('**/GrowlInstaller\Growl_v2.0.msi') }}
           restore-keys: |
-            ${{ runner.os }}-growl-installer
+            ${{ runner.os }}-growl-installer-
       - name: Download Growl Installer (Windows)
         if: "${{ matrix.os == 'windows-2019' && steps.cache-growl.outputs.cache-hit != 'true'}}"
         run: >
@@ -143,9 +143,9 @@ jobs:
         uses: actions/cache@v2
         with:
           path: GrowlInstaller
-          key: '${{ runner.os }}-growl-installer'
+          key: ${{ runner.os }}-growl-installer-${{ hashFiles('**/GrowlInstaller/Growl_v2.0.msi') }}
           restore-keys: |
-            ${{ runner.os }}-growl-installer
+            ${{ runner.os }}-growl-installer-
       - name: Add Growl Installer to Path (Windows)
         if: "${{ matrix.os == 'windows-2019' }}"
         run: 'echo "C:\Program Files (x86)\Growl for Windows" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8'