Go to Safe Mode and perform the uninstall, then reinstall Firefox.

You might also use Revo Uninstaller Portable to get completely rid of the previous version.

Alternatively, follow the below directions.

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.

Finally managed to delete the install files and all of the old Firefox install. Had an old copy of 41.xx and reinstalled it and it works fine. Will not be doing any more upgrades until the install files can extract without a glitch. One thing it taught me is how much is detest Internet Explorer and Edge. Thanks for your suggestions.

Keep this in mind please that when a solution is offered come back and tell if worked or not as there is always another solution like last person said oh found file on another site....well if you found any where else but Mozilla....had to give anti-malware info

So come back before go do it alone as ver 41 was not the answer.

Keep this in mind as the place to get your installer : https://www.mozilla.org/firefox/all/ Full Version Installer

Version 41 is a security risk and is not supported and no longer safe to use for every day use, but 52.5.0 ESR is. It will continue to get security updates until May 2018, and you can download and install it from this page: https://www.mozilla.org/en-US/firefox/organizations/all/ Note : Legacy Extensions will be deleted or removed in any version update after May 2018.

Please let us know if this solved your issue or if need further assistance.

I am glad to hear that your problem has been resolved. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution more easily.

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