This could be caused by the landing of these bug fixes that caused some extensions to get broken.

• Bug 866537 - Several extensions broke (in a way that breaks the browser) after bug 697319
• Bug 697319 - First browser should be dynamically created to allow honoring of browser.tabs.remote pref

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

You can use this to start Firefox in Safe Mode and disable all extensions:

• Help > Restart with Add-ons Disabled
• https://support.mozilla.org/kb/Safe+Mode

See also: http://forums.mozillazine.org/viewtopic.php?f=23&t=2697449

Thanks for the link however I'm unsure how to get back my old session

As when I restart with add ons disabled I cant bring my old session back up

any ideas on how I can bring my old session back up ?

Did you keep a copy of the sessionstore.js file?

If you start Firefox more than once then you lose the version that had session data of those tabs.

• http://kb.mozillazine.org/sessionstore.js
• http://kb.mozillazine.org/Session_Restore

Yes the files are still there however I cant access it in the add ons disabled mode

You need to disable (tab) extensions that watch an onload event.
Then you should be able to start Firefox in normal mode and your session should be restored.

How do I disable tab extensions Ive googled it and no luck

any further instructions on how to do this would be most appreciated

If it works in normal mode with all extensions (Tools > Add-ons > Extensions) disabled then try to find which extension is causing it by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: "Firefox > Quit Firefox"; Linux: "Firefox/File > Quit")

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