That depends on just what the program did. We do not recommend using any other program to 'clean' Firefox as the wrong files could be corrupted. Also, the browser can be set up to clean itself. ----------- Restore Bookmark Backups Firefox automatically makes backups of the bookmarks. These are stored in the '''bookmarkbackups''' folder. Open the '''Bookmarks Manager; ''' Press the '''Alt''' or '''F10''' key to bring up the toolbar, and select '''Bookmarks. ''' Hot key is '''<Control> ''(Mac=<Command>)'' <Shift> B. ''' Once the window is open, at the top of the page, press the button labeled '''Import and Backup. ''' Select '''Restore. ''' From the list, pick the file you want and click it. The backups are stored in a '''jsonlz4 file''' named something like this; bookmarks-2016-06-29_1424_enD1GTH ya0JmicnYWg4V4g==.jsonlz4 In this example; 2016-06-29 = date created, 1424 = number of entries. https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them https://support.mozilla.org/en-US/kb/recover-lost-or-missing-bookmarks