diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 4803d34ec..57e4062c9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -276,9 +276,11 @@ jobs:
 
     - name: Tidy cache
       working-directory: ${{ env.DEV_DRIVE_WORKSPACE }}/src
-      shell: bash
+      shell: pwsh
       run: |
-        find ${{ env.DEV_DRIVE_WORKSPACE }}/cigocacher -type f -mmin +90 -delete
+        Get-ChildItem -Path "${{ env.DEV_DRIVE_WORKSPACE }}\cigocacher" -File -Recurse |
+          Where-Object { $_.LastAccessTime -lt (Get-Date).AddMinutes(-90) } |
+          Remove-Item -Force
 
   win-tool-go:
     # windows-8vpu is a 2022 GitHub-managed runner in our
diff --git a/cmd/cigocacher/disk.go b/cmd/cigocacher/disk.go
index e5a8d04f8..9537e8126 100644
--- a/cmd/cigocacher/disk.go
+++ b/cmd/cigocacher/disk.go
@@ -53,7 +53,7 @@ func (dc *DiskCache) Get(ctx context.Context, actionID string) (outputID, diskPa
 				dc.logf("disk miss: %v", actionID)
 			}
 		}
-		return "", "", err
+		return "", "", fmt.Errorf("failed to os.ReadFile in Get: %w", err)
 	}
 	var ie indexEntry
 	if err := json.Unmarshal(ij, &ie); err != nil {
@@ -146,7 +146,7 @@ func (dc *DiskCache) Put(ctx context.Context, actionID, outputID string, size in
 		return "", err
 	}
 	if _, err := writeAtomic(actionFile, bytes.NewReader(ij)); err != nil {
-		return "", err
+		return "", fmt.Errorf("atomic write failed: %w", err)
 	}
 	return outputFile, nil
 }