Why Is My Userscript Not Working? A Practical Troubleshooting Checklist

When a userscript does not work after installation, the cause is not always a broken script. Often the script is disabled, the page does not match its rules, the browser blocks a permission, or the target website has changed.

Check whether the script is enabled

Open the Tampermonkey dashboard and make sure the script is enabled. Also confirm that the browser extension itself is active, especially if you are testing in a private or incognito window.

Check the website match rules

Userscripts usually run only on selected domains or URL patterns. A script for example.com may not run on www.example.com, a mobile domain, or a localized version of the same site.

Refresh the page and update the script

After installing a script, refresh the target page. If the script has an update available, install the latest version before spending time on deeper debugging.

Review browser permissions

Some scripts need permissions for downloads, clipboard access, cross-domain requests, or opening new tabs. Browser settings and extension permissions can affect these features.

Consider website changes

If a script worked before and suddenly stops, the target website may have changed its layout or code. In that case, the script may need an update from its maintainer.

Summary

Start with the simple checks: enabled status, URL matching, page refresh, and updates. These steps solve most userscript issues before advanced debugging is needed.