Hi,

Please uninstall the previous version of Firefox using control panel to prevent conflict with the new version of Firefox. Also, please delete the folder "Mozilla". Use Windows key+ R then type %appdata%.

Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall 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.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All of them.

Download Firefox Full Installer For All languages And Systems {web link} Save the file. Then;

Using your file browser, open the Programs folder on your computer.

Windows: C:\Program Files C:\Program Files (x86) Mac: Open the "Applications" folder. Linux: Check your user manual.

Look for, and rename any Mozilla and Firefox folders by adding .old to them.

Now run the full installer. If all goes well, remove the OLD folders when you are done.

Fred and Adreil, Thanks for the instructions. I happened to notice that a bar appeared at the top of the browser window that said something like "upgrade to the latest version of Firefox". I clicked on that, and it seems to have successfully updated me to 36.0.1 without the need to uninstall first.

That was very good work. Well Done. Please flag your last post as Solved Problem so other will know.

rxnb90 said

Fred and Adreil, Thanks for the instructions. I happened to notice that a bar appeared at the top of the browser window that said something like "upgrade to the latest version of Firefox". I clicked on that, and it seems to have successfully updated me to 36.0.1 without the need to uninstall first.

Hi, now you are in stable latest release version, before probably you have a previous (31.3.0) esr version. :-)

cheers

Hello,

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.

Thank you for contacting Mozilla Support.