Hello, To recover lost bookmarks, do this : Click menu button>bookmarks>manage bookmarks. At the top of library window, click Import and backup, and hover over restore and select most recent date before it went missing. If not, you can go to your profile folder ('''%APPDATA%\Mozilla\Firefox\Profiles\'''), then find your default profile (usually ends with .default or .default-release), then open the bookmarkbackups folder, then transport a backup in file explorer to your main profile. It is also possible firefox has created a new profile. If so, go to about:profiles, then find a profile named default-release, and click launch profile in new browser. after that, set it as default.