Firefox will not launch. Using for years. Uninstalled and installed twice. Lots of CPU usage, but UI does not launch, ever. Win10 - 1709.
The "question" field says it. After a recent MS update, firefox just stopped launching a UI. It was my default browser. I had to kill the firefox process (which was using a significant amount of CPU cycles/time, without any UI being generated) in Task Manager before being able to uninstall and reinstall firefox (from your web site) multiple times. No joy. Had to revert to MS Edge (which is not too bad, BTW).
All Replies (1)
Hi, hold down the Shift key when you start Firefox to start in Safe Mode. More - Diagnose Firefox issues using Troubleshoot Mode.
If it works in Safe Mode, disable any theme or add-ons you have - Add-ons Manager (Ctrl+Shift+A) > Themes/Extensions and restart Firefox; then if it's OK, re-enable them one by one until you find the culprit. You may need to restart Firefox after enabling some add-ons.
If it still won't start, try 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. Using another browser, download Firefox from https://www.mozilla.org/en-US/firefox/all/ and save the file to somewhere convenient on your computer.
Now delete the Firefox installation folder which should be in one of the following locations - C:\Program Files\Mozilla Firefox C:\Program Files (x86)\Mozilla Firefox
You can now double click the file you previously downloaded to install Firefox.
If your question is resolved by this or another answer, please take a minute to let us know. Thank you!