Hello,

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.

Thank you. Now to Download, it has to be from this computer (not mine), or if you mean my laptop where the problem has occurred, it would be IE as it's the way I have to connect to the Net.

I have tried the latter partially. But after downloading and choosing to Run, it immediately goes to Set-Up Wizard.

So, I am here- and hope you can clarify. At any rate, if I do let the Wiz do its stuff, would I then have Firefox Winows or FFMenu you mention in #2? thanks

Grab the full, off-line installer from here: https://www.mozilla.org/en-US/firefox/all/

And save it to a USB Flash stick, using either computer.

Thanks, I've done that, FF Setup 39.0 is now extracted through USB and the Set up Wizard is shown. Do I go and continue (clicking Next) and THEN save to the computer, which means I have downloaded it to the computer?

I am just trying to decipher now from having it on my USB and then continuing what Tyler above wrote - that it's now in C:\Program files where I'd go to delete the installation folder. I want to make doubly sure of the exact step-by-step before I re-install

NO, don't start the installer on the "borrowed" computer. Plug that USB stick into the computer that you are fixing and run the Setup to install it there. Firefox should pickup your old / existing Profile, as it is supposed to do.

Standard or Custom....I gather Standard?

Try to rename (or delete) the sessionstore.js file in the Firefox profile folder to avoid reopening the previous session. Deleting sessionstore.js will cause App Tabs and Tab Groups and open and closed (undo) tabs to get lost and you will have to recreate them (make a note or bookmark them if possible).

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

You can check if you can start Firefox in Safe Mode by holding down the Shift/Options key.

Thanks. So, you first mean that I am installing Standard from the USB that Ed-meister instructed?

Then, I go to the Profile folder and your instructions? I appreciate the input.

I'm not sure if you would have to reinstall Firefox if there is only a problem with your current profile folder.

Note that a reset tries to recover some data from the old to the new profile and this can possibly carry over a problem.

If you have a problem with accessing the current Firefox profile folder then try to use the Profile Manager to create a new profile.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox
• https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile

I have been able to get to Choose User Profile where there is only a Default listed (This happened while I am connected via IE) I am unsure whether I go to Create Profile, Rename, certainly not Delete, I guess. Below that do I check Work Offline? The box already checked is Use the selected Prof without asking at Start Up

Below that is Start Firefox and Exit boxes.

Do I change the name as previously suggested? and work on or off line...

I will have to leave this helpful forum for support for a few hours. Thanks

If you can't start Firefox with the current default profile then try to create a new profile. A rename won't have effect as this only affects the name as shown in the Profile Manager.

Hi The old Firefox still does not open when I click on it. Thus, if I do create a new Profile and Firefix does open, without the old data, bookmarks etc., how can I go to the Old default Profile to copy and transfer that to the new one/ The issue is still not being able to Open and access the original Firefi, no?

See:

• https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

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