1.2 Backing Up

Thorin-Oakenpants edited this page Dec 7, 2017 · 10 revisions

Hopefully you have read what a user.js does, and how it works. It can have a profound effect on all your settings and data. The ghacks user.js is pretty comprehensive, and no one size fits all - therefore, it is highly recommended that you backup before using it (or use a new or copied profile for testing).

The complete and easiest way to backup is to copy your entire profile directory when Firefox is closed. This directory contains many items that a user.js, with certain preferences, can wipe, such as cookies, site specific settings, saved passwords and login names, browsing + download + form history, disk cache, and more. Just backing up the prefs.js file is NOT enough, and not recommended by this wiki.

To find your profile directory, go to about:profiles (note: this does work with portable Firefox). This will list all profiles, so make sure to select the one that is marked as the profile in use. You will see an Open Folder button which you can click.


When copying your profile directory, it is advised that Firefox be closed. Rename your copied folder to something meaningful, and keep the original name (for an easy rollback). For example, if the profile folder is called jiu9k8gm.default. A backup copy might be called jiu9k8gm.default-2017-03-22 or jiu9k8gm.default-pre-ghacks-userjs.

Be aware, that this is your entire profile. So rolling back will not keep any new cookies, saved passwords, bookmarks, extension changes and the like. The next wiki section outlines some methods you could use to implement and test out the user.js and various preferences.

You can’t perform that action at this time.
You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Reload to refresh your session.
Press h to open a hovercard with more details.