diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 91a4fe8..b335b67 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -44,7 +44,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: cache apt packages
-        if: startsWith(matrix.os, 'ubuntu')
+        if: startsWith(matrix.platform.os, 'ubuntu')
         uses: awalsh128/cache-apt-pkgs-action@latest
         with:
           packages: libasound2-dev