Hello, Your profile (where your information is stored) should not be altered. The best method is re-installation (instructions below); however, if you can not do this, try copying this folder (as another backup just in case) then rename that back to /Mozilla Firefox/ Certain Firefox problems can be solved by performing a ''Clean reinstall''. This means you remove your Firefox program files and then reinstall Firefox. This process does not remove your [[Profiles - Where Firefox stores your bookmarks, passwords and other user data|Firefox profile]] data (such as bookmarks and passwords), since that information is stored in a different location. To do a clean reinstall of Firefox, please follow these steps: '''Note:''' You might want to print these steps or view them in another browser. #Download the latest Desktop version of Firefox from [https://www.mozilla.org mozilla.org] (or choose the download for your operating system and language from [https://www.mozilla.org/firefox/all/ this page]) and save the setup file to your computer. #After the download finishes, close Firefox. #*'''Windows:''' Click the Firefox menu [[Image:Fx57Menu]], then click "Exit". #*'''Mac:''' Click the Firefox menu at the top of the screen, then click "Quit Firefox". #*'''Linux:''' Click the Firefox menu [[Image:Fx57Menu]], then click "Quit". #Delete the Firefox installation folder, which is located in one of these locations, by default: #*'''Windows:''' (Note: Check both folders.) #**C:\Program Files\Mozilla Firefox #**C:\Program Files (x86)\Mozilla Firefox #*'''Mac:''' Delete Firefox from the Applications folder. #*'''Linux:''' If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see [[Installing Firefox on Linux]]. If you downloaded and installed the binary package from the [http://www.mozilla.org/firefox#desktop Firefox download page], simply remove the folder ''firefox'' in your home directory. #Now, go ahead and reinstall Firefox: ##Double-click the downloaded installation file and go through the steps of the installation wizard. ##Once the wizard is finished, choose to directly open Firefox after clicking the Finish button. More information about reinstalling Firefox can be found [[Troubleshoot and diagnose Firefox problems#w_4-reinstall-firefox|here]]. <b>WARNING:</b> Do not use a third party uninstaller as part of this process. Doing so could permanently delete your [[Profiles|Firefox profile]] data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. <u>These cannot be easily recovered unless they have been backed up to an external device!</u> See [[Back up and restore information in Firefox profiles]]. <!-- Starting in Firefox 31, the Firefox uninstaller no longer lets you remove user profile data.Ref: Bug 432017 and https://support.mozilla.org/kb/uninstall-firefox-from-your-computer/discuss/5279 [Fx31] Windows uninstaller will no longer offer the option to remove personal data --> Please report back to say if this helped you! Thank you.

I copied '''/Mozilla Firefox.bak/''' to a new folder named '''/Mozilla Firefox/ ''' When I clicked the now grayed out FF icon it took a moment, but all seems back to normal - and the previous session could be recovered! Thank you!