Bookmarks https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data Firefox may have created a 2nd Profile if that is what you are using now. https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles Information can be recovered if so.

Last person could not start Firefox.

Comodo software ? If so Update and go to their forum as is incompatible update. Need to see which KB file came in Settings --> Updates & Security --> View Update Files

Please let us know if this solved your issue or if need further assistance.

Tried this and the user files AppData are also empty. I did find a new folder of favorites in a now hidden downloads file and copied the file to the desktop after I sent off my original question. I tried every import option however I can't get the bookmarks into Firefox. Any Ideas?

I found JSON file with my bookmark back up. How do I get this into Firefox? Never mind, this is a brand new file and has only about 5 bookmarks. I would love to know what happened to my originals. Can't find a Firefox profile anywhere