Hello,

Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Thank you.

I have this problem too, and did a search and found this info. I use MSN games and every time I try to sign in, I get this message, or another one. Not sure what the other one is, happens often. I don't know how to use safe mode, but will learn. http://controledescripts.mozdev.org/ I installed this add on as suggested and will add MSN games to it, so that I am hoping it will help. Firefox crashed the other day, while I was playing a game on MSN, and working in Word 2013 on-line, searching for templates. I was signed in twice, and think that it shut me down. Do you think this is the problem? And will the script add on help prevent it in the future? Thanks for reading....