Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

These can't get your data back, but will help in the future.

These add-ons can be a great help by backing up and restoring Firefox

FEBE (Firefox Environment Backup Extension) {web link} FEBE allows you to quickly and easily backup your Firefox extensions, history, passwords, and more. In fact, it goes beyond just backing up -- It will actually rebuild your saved files individually into installable .xpi files. It will also make backups of files that you choose.

OPIE {web link} Import/Export extension preferences

gooliegirl2000 said

So whenever this happens with my firefox, I just quit out of it and it brings back all my bookmarks, toolbar and in my tab. On Tuesday it happened and I even restarted my computer and still haven't be able to get my bookmarks back. I backup my bookmarks/history every day and even with trying to use the older backups it keeps saying no. What can I do?

How are you doing that backup? And what format is that backup in? Like JSON or what?

Firefox automatically backs up the users bookmarks (when they have been changed) daily, but doesn't backup browsing or downloads history.