You can do a check for corrupted and duplicate fonts and other font issues:

• http://www.thexlab.com/faqs/multipleappsquit.html - Font Book 2.0 Help: Checking for damaged fonts
• http://www.creativetechs.com/iq/garbled_fonts_troubleshooting_guide.html

Question owner

But I never installed any fonts...

Even if you haven't installed new fonts yourself then it is still possible that one or more fonts aren't working properly, so you can still test them with the Font Book application just to be sure.

Try to disable hardware acceleration in Firefox.

• Firefox > Preferences > Advanced > General > Browsing: "Use hardware acceleration when available"

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

• https://hacks.mozilla.org/2010/09/hardware-acceleration/

Question owner

The "Use hardware acceleration" was already checked, so I unchecked it. It still doesn't seem to do the trick... Am I out of hope?

Question owner

How do I check for corrupted fonts? I clicked on those two links and I couldn't figure out what to do (i'm really technologically slow)

I had this problem too, so just in case I ran a Malware scanner, it found and removed some questionable files and so far Firefox seems to be working as normal again.

Question owner

Where can I get a Malware scanner? Do i need to scan even though I have a Mac?

I used Malwarebytes http://www.malwarebytes.org/products/ which is free. I don't think they have a Mac version though and even though you're on a Mac, it might be worthwhile to scan for malware. Do a search for a Mac malware scanner, there will probably be a free versions out there.

See:

• Font Book 198: Validate fonts: http://support.apple.com/kb/PH5958
• Font Book 198: Resolve duplicate fonts: http://support.apple.com/kb/PH5960

Question owner

I tried it.. nothing works :( I don't know what to do..

I was having the same problem.... But I keep forgetting that when you upgrade firefox... or it updates automatically... you need to right click on the firefox start up icon, go into properties, click on the compatibilities tab, and put a check in the "Run This Program As An Administrator" box, then hit apply. Start Firefox, and it should work OK. Problem is...each time you upgrade firefox and/or I think Adobe flash... you need to make sure that box is checked. This is on Firefox 15.0.1 with Adobe Flash 11.4.402.278 all up to date, Windows 7 64bit. If Firefox has Adobe flash add-on, it needs to run in admin mode or it will crash.

cutmetal,

Checking your username for previous posts (here) I see that you also posted the same information in a number of other threads today.

You don't normally need to check the "Run This Program As An Administrator" box in Firefox -> Properties -> Compatibility tab, to prevent crashes after updating Firefox or Flash. If you need help with this issue, you should ask a new question. You can use this link as a starting point: https://support.mozilla.org/questions/new

Modified October 5, 2012 9:46:56 AM PDT by AliceWyman

Alice... I was not seeking an answer, as this was the solution that was causing mine to crash after updating firefox and flash. After much frustration, this solved it for me. I posted in all the forums where others were having a crash, as it may be the same problem and they seem to be related to what I was having. It was posted in the hopes it would solve their problem. All they can do is try it..... Then the group at Mozilla.org can work out why Firefox with the latest flash needs admin rights or not. I also have zone alarm set pretty high on security... so it could be that it does need to be run as admin... it is worth a try...