Recover user data missing after Waterfox update
If Waterfox starts up without your bookmarks, passwords, saved tabs and other settings, check whether your data is available in a different profile. This can happen because Waterfox creates a dedicated profile for each Waterfox installation.
To recover your Waterfox data and settings from another profile:
Type about:profiles into the Waterfox address bar and press the Enter key. This will open the About Profiles page.
This page should list at least one profile and could list many. The profile that Waterfox is currently using will have this:
This is the profile in use and it cannot be deleted.
Please do not delete any profiles. Don’t use any Remove buttons. If you have another profile listed on this page, it may contain your missing profile data. You can click the Launch profile in new browser button to open another Waterfox window using that profile. If the other profile doesn’t contain your missing data, simply close that new window. If it does contain the missing data, you can set it as the profile that Waterfox will open by default. Click the Set as default profile button for that profile and Waterfox will use it automatically the next time you open Waterfox.
For more information about managing Waterfox profiles, see the Profile Manager - Create, remove or switch Waterfox profiles article.