sometimes due to multiple tabs running at the same time could create problem due to loading of some heavy website. So don't worry mozilla is trying to solve this problem.

How long would you say that Windows shows Not Responding on Firefox's title bar? Or should I say, how long does it take to recover from this?

Some other threads have noted problems with IE Tab extensions in Firefox 40. Could you disable IE Tab and see whether that makes any difference? You can do that on the Add-ons page. Either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then you can find it on the right.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Any difference?

Could you test in Firefox's Safe Mode? That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Diagnose Firefox issues using Troubleshoot Mode.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

I'm not sure how long it will take to know whether there is any improvement, but does that make a difference?

It just flickers 2-3 times. I reset firefox and tried disabling certain add ons but it still does it even with no add ons. I'll try the safe mode option and see if that helps.

I'm getting constant flickering and I can't use the browser. It is constantly crashing and needs to be force closed using Task Manager. Issue also appears in safe mode. Help?

Hi hpgirl18, sorry to hear about the crashes. Or maybe they are freezes, since it sounds like Firefox is not closing and presenting a crash dialog.

If you have submitted crash reports, please check the last section of the support article "Firefox Crashes" for steps to get the crash report IDs from the about:crashes page; those are helpful to support volunteers and we can't access the reports without those unique codes.

Also, could you start a new question and include your system information? You can use the following link. Scroll down past the suggestions to continue submitting your question: https://support.mozilla.org/questions/new/desktop/fix-problems