Do you have McAfee Site Advisor plugin and is it enabled? If so, disable it and see if that helps.

Mozilla had disabled this plug-in several months ago because of several issues it was causing. But after upgrading to 6.0.2 I noticed it was enabled, again, and I was having significant issues with memory and CPU usage that primarily affected Firefox and McAfee anti-virus scans but also slowed down overall system responsiveness.

A couple of hours ago I disabled it and almost immediately all the issues I'd been experiencing went away.

Hi, i actually don't use McAfee antivirus, but I do have AVG installed as a plugin in Firefox. I've disabled the plugin, but I still have the "freezing" issue.

Thanks for your help anyway.

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

See also:

• http://kb.mozillazine.org/Firefox_hangs
• https://support.mozilla.com/kb/Firefox+hangs

Safe mode did not solve the issue with firefox 6.02 freezing up in the way that topic creator explained.

A blog post by Marco Bonardo, a Firefox developer, regarding this issue :

Is your Firefox freezing at regular intervals?

We've identified a bug that may cause, under certain circumstances, periodic freezes of the Firefox UI, in terms of a short freeze every about 9 minutes. This only affects a small amount of users, so, if you don't notice this behavior, you can stop reading.

If you think you are suffering this bug, stay sure it will be solved in Firefox 8. In the meanwhile, here is a simple workaround to fix the issue:

1. Install my Places Maintenance add-on
2. Go to about:addons and open the add-on Options dialog
3. Select the Expire operation and click Execute
4. If you wish, uninstall the add-on (it's restartless, so the process is straight-forward)