One common diagnostic step is to disable Firefox's use of hardware acceleration. There was a bug on the Retina display where this messed up Flash players, but hopefully that has been fixed by now (or maybe you don't have a Retina display).

Firefox menu > Preferences > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

This takes effect the next time you Quit and restart Firefox.

More generally, when Firefox crashes, it usually records information about what was happening at that moment. You can submit that data to Mozilla and share it with forum volunteers to see whether it points to the solution. Please check the support article "Firefox Crashes" (especially the last section) for steps to get those crash IDs, and then post some of the recent ones here.

OK - I made the suggested changes. Restarted Firefox. Ran for 30-60 minutes....crash...It's got a similar crash reason to the others: Firefox 25.0.1 Crash Report [@ libobjc.A.dylib@0x1222b ] Crash Reason EXC_BAD_ACCESS / 0x0000000d

Could you provide a link to the crash report on the crash stats server? I don't know how to look it up by the information you provided.

https://crash-stats.mozilla.com/report/index/719e4638-af64-46c2-844f-2d08a2131210

Hmm, seems like a rare one, there aren't any specific bugs associated and only one other report in the past 7 days (also on Mac). It might help to post some of the other crash reports in case they have more information.

Is there anything noticeably different about the pop-up windows that cause problems compared with those that do not? For example, if you create a new window using Command+n and then close that, does Firefox crash?

Nothing unusual being done during these crashes. I'm not sure if all these are when a pop-up is closed, but here's the last 5 crashes

1. https://crash-stats.mozilla.com/report/index/0fb3e23c-f3ae-4062-abc0-2818e2131210
2. https://crash-stats.mozilla.com/report/index/6448aab0-bd9b-424b-ad50-5bc032131210
3. https://crash-stats.mozilla.com/report/index/89d0edb9-440d-4009-8d0a-24df62131209
4. https://crash-stats.mozilla.com/report/index/f4f42646-2b04-47fb-b821-ccd332131208
5. https://crash-stats.mozilla.com/report/index/8f99567c-03fb-4f96-9138-2c1a12131206

_{formatted as numbered paragraphs ~J99}

It doesn't always happen with a pop-up...just sometimes.

I just did a few command-n new windows without crash.

Two of those are roughly the same as the earlier one you posted, Mac-specific but without a discussion. Two are linked to an OS X 10.9 bug that's on file which at least one tester was able to trigger with rapid window or tab changes using keyboard shortcuts. But no specific solution/workaround as of yet. The fifth one is linked to a bug that occurs in private browsing mode but again is not solved. So that's probably not very helpful to you.

Here's one more (just happened). Logged in to a bank site. Clicked to read a message from them which opened in a new window. When I closed the window, Firefox crashed https://crash-stats.mozilla.com/report/index/d403844d-2831-4963-92f8-ba80c2131211

Hi Gatnus, that's the one that links to the bug so you could scroll down the bug link and read what they've discussed so far. Unfortunately, I don't have enough information to propose a workaround and I'm very ill informed about Mac OS X.

Try to remove the Firefox plist file (org.mozilla.firefox.plist).

• http://www.macfixit.com/article.php?story=20060606082246983 How .plist files become corrupt and troubleshooting the results

Go to "~/Library/Preferences" and remove the plist file for Firefox (org.mozilla.firefox.plist)

You can also 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