Join the Mozilla’s Test Days event from Dec 2–8 to test the new Firefox address bar on Firefox Beta 134 and get a chance to win Mozilla swag vouchers! 🎁

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Firefox crashes before it opens

  • 2 replies
  • 2 have this problem
  • 5 views
  • Last reply by cor-el

more options

When I try to run Firefox I get a screen saying that it has crashed. Firefox won't open at all. I installed the newest version because I thought it might be a problem with the older version I was running but I still received the same crash notification and Firefox still won't open.

When I try to run Firefox I get a screen saying that it has crashed. Firefox won't open at all. I installed the newest version because I thought it might be a problem with the older version I was running but I still received the same crash notification and Firefox still won't open.

All Replies (2)

more options

Hey rcano,

Have you tried starting Firefox in Safe Mode? Hold down "shift" while Firefox is starting up. If the crash doesn't happen in Safe Mode, you should read Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.

There is also a lot of useful stuff in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) Knowledge Base article. If you've recently upgraded, you might want to check out this article as well.

Hopefully this helps!

more options

Sounds that you may have caught some malware (efcaby.dll and effeef.dll).


Do a malware check with some malware scanning programs on the Windows computer.
You need to scan with all programs because each program detects different malware.
Make sure that you update each program to get the latest version of their databases before doing a scan.

See also: