Do you have Avast security software?

• bug 1087674 - Firefox won't close with Avast 2015 10.0.2206 when HTTPS scanning is enabled

Please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html

Make sure that you have the latest Firefox 33.1.1 release and also the latest updates of all security software.

no i haven't avast security. i am using windows defender. Firefox 33.1.1 started crashing after doing the upgrade. Crash report is made after you close the browser.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

You can check for issues caused by plugins and set all plugins to "Ask to Activate" on the "Firefox/Tools > Add-ons > Plugins" page (plugins are not affected by Firefox Safe Mode)

• https://support.mozilla.org/kb/Troubleshooting+plugins

See also:

• http://kb.mozillazine.org/Firefox_crashes
• https://support.mozilla.org/kb/Firefox+crashes

The crash report flagged;

KERNELBASE.dll = Windows ?

combase.dll = Windows

ntdll.dll = Windows

Perform a System File Check to fix corrupted system files http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html

See if there are updates for your graphics drive drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration