Could you take a look at my reply here for suggestions: https://support.mozilla.org/questions/1177789#answer-1012188

''mschuster [[#answer-1013797|said]]'' <blockquote> There is only one bookmark backup file in the Waterfox > Profiles folder. <br> There was an automatic update from 54.0.1 to 55.2.0 on October 4th and all the bookmarks were gone. </blockquote> I don't suppose that backup file looks like it would be useful. Is it too new? If you want to try restoring it, I suggest creating a safety backup first. This article has both the backup and the restore procedures: [[Restore bookmarks from backup or move them to another computer]] Do you have any other backups of your profile folder created by backup software/services? Windows occasionally may capture a snapshot of your application data when it installs updates. This would be in a restore point, but please do not use the Windows system restore feature as that may destroy newer data. Instead, I suggest using a third party tool to view the contents of your restore points. First, make sure you can view hidden files and folders: https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files This is the program: http://nicbedford.co.uk/software/systemrestoreexplorer/ In the most recent restore point, check along the usual path of your profile folder to see whether it is in the restore point and whether it has any bookmark backup files. You can copy out anything promising to a convenient location.