diff --git a/.github/workflows/windows-native-preparation-benchmark.yml b/.github/workflows/windows-native-preparation-benchmark.yml
index 709c1dbd4f6..8b98ae9f737 100644
--- a/.github/workflows/windows-native-preparation-benchmark.yml
+++ b/.github/workflows/windows-native-preparation-benchmark.yml
@@ -16,6 +16,9 @@ on:
 permissions:
   contents: read
 
+# Candidate source must not write caches in the dispatch branch's scope.
+cache-mode: read
+
 concurrency:
   group: windows-native-preparation-comparison-${{ github.ref }}
   cancel-in-progress: false