Hello! Please try refreshing Firefox. If this not help please see solution 2.

The Refresh feature (called "Reset" in older Firefox versions) can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information.

Note: When you use this feature, you will lose any extensions, toolbar customizations, and some preferences. See the Refresh Firefox - reset add-ons and settings article for more information.

To Refresh Firefox:

1. Open the Troubleshooting Information page using one of these methods:
   • Click the menu button , click help and select Troubleshooting Information. A new tab containing your troubleshooting information should open.
   • If you're unable to access the Help menu, type about:support in your address bar to bring up the Troubleshooting Information page.
2. At the top right corner of the page, you should see a button that says "Refresh Firefox" ("Reset Firefox" in older Firefox versions). Click on it.
3. Firefox will close. After the refresh process is completed, Firefox will show a window with the information that is imported.
4. Click Finish and Firefox will reopen.

SOLUTION2:

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 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.

1. Download the latest Desktop version of Firefox from mozilla.org (or choose the download for your operating system and language from this page) and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (or open the Firefox menu and click the close button ).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • 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 Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

More information about reinstalling Firefox can be found here.

WARNING: Do not use a third party uninstaller as part of this process. Doing so could permanently delete your Firefox profile data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be easily recovered unless they have been backed up to an external device! See Back up and restore information in Firefox profiles.

Please report back to say if this helped you!

Thank you.

The old Sync version that was used in Firefox 28 and older will be discontinued in one of the next months (possibly September), so if you still use this older Sync version then you need to upgrade to the new Sync version.

Did you use this website?

• https://accounts.firefox.com/settings

The old Sync account was using this website:

• https://account.services.mozilla.com/

The new Sync version used in current Firefox releases is completely different than the version that was previously used. Firefox 29 and later versions use a new Sync version that use a Firefox account and only require to enter the name and password and you no longer need to enter a Sync (recovery) key (the Sync key is automatically generated from the password of the Firefox account). If you change the password of the Sync account or request a new password because you do not remember the password that this will remove (reset) all data stored on the Sync server.

You can delete the signedInUser.json file in the Firefox profile folder and delete the Weave folder (Sync was formerly named Weave). If that isn't enough then delete the prefs.js files to reset all prefs and maybe also delete the compatibility.ini file to reinitialize the profile.

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

bkglass said

Firefox wants me to upgrade Sync. I have been using sync and have a Firefox account. When I try to sign in to upgrade, Firefox says "unknown account". In the Firefox options tab, my account does exists and shows my account email. I wanted to double check, so I tried to change my password by entering my current password in the 'new password' field... Firefox says 'you can't use your current password for your new password. This confirms that I have an account and it should work. I tried to fill out the 'lost my password' field to to maybe have a new one emailed to me, but Firefox says my account email does not exist... But in the options tab in the browser, it DOES exist. I have no idea what the problem is, how to fix it, or where to find help.

Thanks for the help cor-el and adriel! I just had to create a 'new' account for the 'new' sync. Maybe I missed it, but I had no idea that there was an 'old' and 'new' Firefox account website.

I think if Firefox was very clear about this fact while telling you to upgrade sync or when someone tries to upgrade using their current 'old' sync account info, I would not have had this problem.

Thanks again for the help!

Hello,

I am glad to hear that your problem has been resolved.

Thank you for contacting Mozilla Support.