Just to rule-out the obvious first, have you logged into your account on the new installation of Firefox? If so are you sure you used the same e-mail address as when you synced the old one?

Just to rule-out the obvious first, have you logged into your account on the new installation of Firefox? If so are you sure you used the same e-mail address as when you synced the old one?

Yes, I logged into the same account. I even hit the "Sync" button before reinstalling the system.

In that case it SHOULD have worked but obviously hasn't.

The thing about c:\Windows.old applied to Windows XP and Vista certainly but has obviously changed at some point since. As I've never used anything newer than Vista I'm afraid I can't suggest anything else.

However for future reference you can manually back-up your passwords. Go to about:logins and then click the three dots at the top right. Under that is an option to Export Passwords. That saves than as a .csv file which you could copy to an SD card or something and then re-import them after re-installing Windows. You can do something similar with your Bookmarks from Bookmarks > Manage Bookmarks.

I accept this isn't any use to you now but may be useful in future or to other people reading this.