I was attempting to install an older version of Firefox onto a different drive than the one I use for the current Firefox. However, after testing out the newly installed Firefox, I launched the current Firefox to find that all my tabs and history had been deleted - which did ''not'' happen the last time I tried this. I've been trying to use software to recover the old data, but I'm not sure which files I should be recovering - nothing I do seems to restore the old history or tabs.