I'm having a similar issue. Firefox crashes ALL of the time when I'm on sites that use flash, so I'm almost positive it's related to Adobe Flash, but testing does not support this. I've uninstalled latest version of flash, then visited these same pages and it still crashes. Then, I've reinstalled it and same thing happens. Finally, I've disabled ALL of my plugins, flash included, and it's still crashes EVERYTIME I visit a site that requires flash.

The only difference I see here is that I'm using FF 4.0 RC1 with Windows 7.

I have a kind have a similar issue to fatpat also but it's not as bad. Adobe Flash Player crashes on certain I visit but it does tend to do that every now and then.

My main is a App in Facebook where it seems not to work properly, I go to bring up my Friend's list of who is online down right hand corner and it takes me a few clicks or so to bring it up.

On top of that I was online in Facebook for a few mins doing some errans and while I was burning something to Disc I went to click on something then my PC shutdown on me and had to reboot itself back up to my Desktop on Windown XP... Very, very weird...

Certain Sites even*

Try going back to the previous version of Flash - 10.1 r102

http://kb2.adobe.com/cps/142/tn_14266.html

I've been looking for the page to roll back to previous version. I had 0 issues with it. THANK YOU!

The problem is FIREFOX . No doubt ! 110 % sure !

What a shame for Mozilla developers / testers ..

rolling back to the previous version works

This problem still exists in firefox 4.0.1 and the latest flash version (10.3.181.22 at the moment).

This version of flash works perfectly in IE, and Opera. Also the bundled flash in Chrome works flawlessly too. Only firefox causes crashes (sometimes only flash and sometimes the whole browser) and sometimes causes hangs until I manually kill plugin-container.

This even happens on a clean profile with no changes/extensions/etc.

PLEASE FIX THIS. WITHOUT FLASH, FF IS USELESS TO ME.

(EDIT: I am not willing to downgrade to a bug ridden old version of flash, there are enough security vulnerabilities in it to make me nervous about using it.)

I have this problem too- yet it does not happen all the time. It has to be a problem caused by Flash because if I disable it then Firefox doesn't hang. Its infuriating and it has been going on for some time: I'm lumbered with Vista as OS but it started some time ago- and quite a lot of Flash updates ago as well; am on Ff 5. I really dont want to move to another browser but I guess its looking like that.

Flash has just been updated again, maybe you could try FF5 again with the new flash.

For good working follow the next steps, its working, for Windows7 with Firefox 4.01 and higher. ( I have tested FF 4.01 and 6.0.) The problem is that when you have used IE there are a conflict between the flash player from IE or other explores and the Flash player from Firefox.

Download from Adobe.com the un-install file: uninstall_flash_player.exe, from http://kb2.adobe.com/cps/141/tn_14157.html. Run this file and when don, remove manual : C:\Windows\SysWow64\Macromed (This is the map were Firefox installed Flash player). Look also to System32. If there a map Macromed, remove this also. C:\Windows\System32\Macromed\. (This the Flash player map for IE). When you cant remove, restart the PC first and try again. Now all the Flash player files are removed. Uninstall Firefox and restart your PC. Now install Firefox again to C:\Program Files (x86)\Mozilla Firebird (Original map) , and update to version 6.0 or download and install Firefox 6.0. Start Firefox and download Flash player: http://get.adobe.com/(eng, us, nl)/flash player/. (select your language in : Eng, us, nl). Do not use another explorer!! Install Flash player and restart the PC. Start Firefox and select a movie from Youtube. If the movie start, stop the movie with the pause button. You must very quickly. Disable hardware acceleration in the movie screen with right click, and make the buffer bigger to 100 KB. Start the movie again. When you do it right, you can play the movie. Don't use IE now!! IE ask you to install Flash player and you have the same problem again. I have tested it.

Now enable IE form the configuration screen>windows part install or remove. Now is the IE removed from your PC and Flash player is working with Firefox. This step is not necessary, but you can not make a mistake and start the IE.

Outlaw53