Exactly the same issue. I rely heavily on FF & Firebug for coding too. Looks like Chrome is the answer - at least temporarily.

I had the exact same problem, version 4 began freezing regularly and the only fix for me was to force quit and re=start my Mac Book Pro. This went on for a couple of days then I decided to download version 4 once again and reinstall over the existing operating version 4. This seemed to correct the problem, so far I have had heavy use of version 4 without any more freezing. So far this is working good for me and it might for you too.....thanks

A Quality control issue... you have managed to freeze Macs, that's some achievement.

Disabled flash player plugin and it doesn't freeze anymore. Plan on reinstalling flash now and hopefully freezing stops.

Downloaded a fresh copy of flash and enabled it on Firefox again. So far, no problems.

jkt610 thank you for the information. I ended up reverting back to 3.6.16 because I was so frustrated with 4.0. If uninstalling flash and reinstalling fixes the problem I may just try a second time to upgrade.

On Ma OS X 10.6.7 and I have the same thing Firefox 4 freezes after a while ... I have about 10 tabs open .. may be this is related to one of them? But normally a tab can crash without altering the rest or is it chrome? I notices some hanging before on some stuff like displaying options etc .... but not too serious .... that is very anoying as you might get stuck while filling a form on the web ... which actually just happened to me this morning!

Firefox needs to fix this quite quickly I think ... or people will move to another browser ...

The thing this didn't happen when I first installed firefox 4 .... so it could be related to recent mac os x updates? The last one was ...a security update 2011-002 version 1.0 on the 29/04, snow leopard font update 1.0 on the 29/04 iTunes 10.1.1, and Safari 5.05 on the 29/04 then back to 22/03 for MAc OS X 10.6.7 update ...could it be the security stuff ?

I had Firefox 4 hang when run for the first time. After reading posts indicating issue with Adobe Flash, I uninstalled flash and reinstalled using the latest version. All works now. I am using Mac OS X 10.6.7, and I had recently migrated from a PowerMac, so I think I still had the older non-Intel Flash. All is good now.

same here , been freezing for some days now . I updated the flash, shockwave etc and have the same problem , Im using MBP with 10.6.7

I have the same problem on my Dell "Hackintosh" running latest 10.6.7. I get random freezes in Firefox 4.0.1. I cannot isolate it to any add-on and I just updated Flash before this trip I'm on and it still does it. It doesn't freeze forever, though. If you wait it out (usually 30 seconds to 3 minutes maybe?), it does come back and continue working normally (CPU is pegged at 100% during the freeze, though). I think maybe some of you have not waited long enough before hitting Force Quit. I'll try re-installing Flash again, though. But I've seen this problem on my PowerMac recently with the latest versions of Firefox 3.x, though on my PowerMac that is a server for my whole house audio/video system (and not before the most recent updates) so I think there's something common between them causing it in the newest releases.

Chrome and Safari are not good solutions, IMO because they have their own problems, at least on a single core CPU like this Netbook. Namely, Webkit browsers seem to come to a crawl on other tabs while loading something new on another/new tab. In short, if I'm reading a forum on one tab and click a link to something on some other site, I CANNOT scroll for squat on the original tab until the new tab stops loading. That seems to be true for Webkit browsers on any platform (may not be as noticeable on multi-core, though if the CPU continues the old tab on another core; I haven't browsed on my MBP recently with them to find out since I usually use Firefox regardless of the computer).

So I have my choice, bad tab flow/multi-tasking ALL the time with Webkit based browsers or random freezes on Firefox once-in-awhile (doesn't happen all the time, just once every couple of hours on average, I think). I'd like to know what it's doing when it happens. It's sitting there long enough. Some kind of bug trace might be helpful.

I've got the same problems but with both FF 4 and Safari 5, running SL 10.6.7 Interestingly the freezing only occurs on my iMac. (My MacBook Pro, also running 10.6.7, hardly freezes except when using Safari 5. FF 4 on my MBP gives me no problems whatsoever.) This past weekend I performed a "nuke and pave" on my iMac, did not re-install Adobe or FF and I'm still having problems. Then I thought maybe it's a memory thing and I reset the PRAM (Opt, Cmd, R, P)...still freezing. Then I tried fixing the desk permissions...still freezing. Per some of the replies here, I'm going to re-install FF 4 and make sure I delete any Shockwaves and Adobe flash players, I'll let you know if it works...

I believe that I have the same problem, but am going to look at it from another take.

My interface freezes, perhaps as a combination between Firefox and OS X. Keyboard shortcuts do no work, neither does alt ~ (to switch between windows) or clicking any part of the interface. I do not get the spinning beach ball of death and OS X doesn't show that the program is not responding.

I am able to reproduce this problem when I click a link to MPG file. Scrubbing back and forth makes the Quicktime plugin freeze or something, and then Firefox entirely does not respond.

Mine freezes since FF4 came out. I always have firebug enanbled. Sometimes it freezes while accessing a menu, even then, the whole menu freezes too. (screenshots with graphical errors: http://screencast.com/t/xWbrsXO4L1x )

BUT, I can unfreeze FF by starting to drag the window!!

(I found out when starting to click like crazy beacause of frustration :p )

Exactly the same situation here. Yesterday I downloaded Firefox 5, hoping it would fix the problem. Nope, it's already froze up on me already today. Force quit seems to be the only (and highly aggravating) way to get it back to working. I prefer Firefox over Safari and all my bookmarks are there. I'd sure hate to have to give up on ole Firefox after all these years.

As far as plug ins and add ons, I only have one and have recently updated it, and the problem persists. I hope with the new version, they may find the bug in the system and can finally get it fixed. I had high hopes when I hit the download button, only to be disappointed.

Several weeks of random freezes and force quits later, FF just keeps getting unresponsive and then freezes. All through the versions 4.x and now at 5.0.1 - same thing.

Have repaired permissions, cleared caches, run periodic scripts, fsck... manually. On Snow Leopard, always the latest version.

Would hate to give up on FF.

I seem to have this same problem as well... Only the entire iMAC graphical user interface seems to lockup... I have to use putty to ssh into the system remotely, sudo into su, and execute "shutdown -r now" in order to reboot... OS version: Max OS 10.6.8 Firefox version: 7.0.1

Both Firefox and the Max OS are up-to-date. I am going to see about using chrome or Konqueror until this issue is resolved.