First, you need to update to Firefox 12. You are running Firefox 5 which has serious security and stability issues (plus 12 is faster).

After you do that, you can try reading How to fix preferences that won't save. It might be able to assist. And if you just want to uninstall the extension, read Disable or remove Add-ons

My extensions don't work on Firefox 12 so that doesn't help me.

I should also point out that if I format my hard drive and re-install Windows and Firefox 5 then I don't get this problem but that's a lot of hassle.

I only get this problem when I install a new version of Firefox when I already have a previous version installed.

So before installing the new version I uninstalled Firefox and selected the option to delete my settings. I then checked my profile folder to make sure nothing was there. I then reinstalled Firefox again and all the same extensions with the same settings as before and I still get this problem.

So it's quite disturbing that I deleted all traces of Firefox yet I get this problem again which makes me think that not everything was deleted.

Do did you update to Firefox 12, and read the preferences not saved article?

I've installed version 12 now.

I did what it said in the "Preferences not saved article" but it didn't solve the problem.

I don't understand why uninstalling Firefox and selecting the option to delete all settings (I checked the profiles were gone) doesn't actually seem to do that as when I reinstall Firefox I get the original problem I mentioned. Yet if I were to format my hard drive and reinstall Windows and Firefox I don't get the problem.

How do I actually remove everything to do with Firefox? Do you have any other suggestions on how to fix it?

I have uninstalled Firefox, deleted the installation directory, and deleted all registry keys yet still when I reinstall Firefox 12 the empty bookmarks toolbar still shows whenever I start Firefox.

Have you gone into your APPDATA folder and removed the Mozilla folder inside there?

Yes. It seems that it's my Multirow Bookmarks Toolbar Plus extension that causes this problem as when I uninstall it I don't get this problem. Any other ideas on how to fix it?

Yes, that is what it is starting to sound like. The developer probably has a bug in the extension causing this. I would contact them to report it.

See:

• http://kb.mozillazine.org/Corrupt_localstore.rdf
• https://support.mozilla.org/kb/Toolbar+keeps+resetting