Comment 10 for bug 88567

I had this same issue, it appears that installing 2.0.0.2 creates signons2.txt from your signons.txt file. Your original file should still remain.

I do not have specifics as to how this migration process is occurring, but I have found that by removing "signons2.txt" solves this problem on the next restart of Firefox.

At that point it converts your signons.txt to signons2.txt again, only this time it works.

I have had little success with many of the solutions listed on mozillazine, including the python script. This has worked on both my Dell laptop with Kubuntu, AND my desktop machine with Debian.