diff --git a/README.md b/README.md
index d0c9b2a..a8912d8 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,17 @@ make build
 
 The built application will be in `build/bin/`.
 
+### macOS Gatekeeper
+
+Since the app is not signed with an Apple Developer certificate, macOS may show "app is damaged" error. To fix:
+
+```bash
+# Remove quarantine attribute
+xattr -cr "Daily Timer.app"
+```
+
+Or right-click the app → Open → Open (first launch only).
+
 ## Usage
 
 ### Setup Meeting