diff --git a/.gitea/workflows/build.yml b/.gitea/workflows/build.yml
index d099ba8..35b8eb3 100644
--- a/.gitea/workflows/build.yml
+++ b/.gitea/workflows/build.yml
@@ -115,7 +115,12 @@ jobs:
           path: build/webapi
           if-no-files-found: error
           retention-days: 7
-
+      - name: Diagnose mounts
+        run: |
+          set -e
+          mount | grep runner-cache || true
+          ls -la /runner-cache || true
+          echo "MARKER $(date -Iseconds)" | tee /runner-cache/__ok.txt
   store-artifacts:
     runs-on: ubuntu-latest
     needs: [build-frontend, build-backend]