Sounds like a clean reinstall is needed to me:

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.

Mkll said

Sounds like a clean reinstall is needed to me: 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.

I'll add to this delete the Mozilla folder as well as just uninstalling it will not remove unknown problems that uninstall doesn't get rid of. But also make sure you back your bookmarks if you have them and then do a complete fresh FF install. And tell us if anything shows up after that.

Roger.

see this page:

• https://support.mozilla.org/en-US/kb/warning-unresponsive-script

If your running any add-ons like NoScript that would be a issue also.

Okay so what about mobile? That stopped working too. Each and every single youtube video I watch, it exits out of fullscreen after an undetermined random amount of time, the screen turns grey and the loading circle just loads and rotates forever. I copy the URL into any other browser and I have zero issue at all. I am not running any no script anything.

ihatemozillaroyally said

Okay so what about mobile? That stopped working too. Each and every single youtube video I watch, it exits out of fullscreen after an undetermined random amount of time, the screen turns grey and the loading circle just loads and rotates forever. I copy the URL into any other browser and I have zero issue at all. I am not running any no script anything.

One never knows over time junk or errors accumulate over time and bad updates will cause unforeseen problems as well. I don't use FF on my Android anymore but use Chrome instead. I do because of sites I log into aren't EN but aka JPN and it translate them making it better to read and understand them. FF has yet to do this so that is why I will not use it for that.