diff --git a/3.5-prefsCleaner.md b/3.5-prefsCleaner.md
index 8f48cbf..daf36a5 100644
--- a/3.5-prefsCleaner.md
+++ b/3.5-prefsCleaner.md
@@ -2,6 +2,8 @@
 
 🟥 Summary: **ALWAYS run prefsCleaner after updating**.
 
+🟥 Warning: **DO NOT DELETE PREFS.JS**. `prefs.js` is a runtime file that includes more than just your pref changes.
+
 ---
 
 🟪 **THE PROBLEM**