I have the same problem

Win 7 home. Two screen. Upgraded to Version 3.6.4 Installed and runs, but nothing opens on the screen. Uninstalled, rebooted, and reinstalled, still nothing. The only way I could get Firefox back was to uninstall and reinstall ver 3.5.10 Great! How do I get the latest version to work?

3.6.4 downloaded and installed yesterday evening and today multiple sites that worked fine every day prior with 3.6.3 now hang on load. Must have restarted Firefox over 50 times tonight. Apparently going to have to go back to an earlier version until they fix this one.

Are you able to get Firefox to start in Diagnose Firefox issues using Troubleshoot Mode at least?

I don't know. I have gone back to version 3.5.10.

If I had to guess, Firefox 3.6.4 was running but the windows were being display somewhere other than on the visible part of my screens!

I have never had this problem with anything else.

How do I stop Firefox automatically updating to a (for me) an unusable version?

How do I know when this problem is fixed, I will not be alone!?

I had the same experience after Firefox updated automatically from 3.6.3 to 3.6.4. Firefox looked as if it was starting up but nothing more happened. Same phenomenon in safe mode and when trying to run the profile manager. I have reverted back to version 3.6.3 which is working fine and disabled automatic update (Tools -> Options -> Advanced -> Update).

Thanks I will do the same. Where can I find a download of Ver 3.6.3  ?

OK, found Ver 3.6.3 installed and works perfectly.

Updated to 3.6.4 and after it checks add-on compatibility I get nothing. No error messages, and no browser window appears. Windows 7 task manager says firefox is running.

Uninstalled 3.6.4 reinstalled 3.6.3 browser window appears, no problem. Conclusion 3.6.3 works fine, but 3.6.4 has some problems which need fixing.

I noticed that after 3.6.4 installed, when I went to run it, the Add-on check would hang. The only way to close it was to select Cancel. Once I did that, Firefox launched, but no web pages would load. Also had to revert to 3.6.3

Have 3.6 working and when it does it's automatic upgrade to 3.6.4 it no longer works and requires me to reinstall 3.6 again for it to work. (Have to do reinstall each time I wish to go online) I get a message that http and https addresses cannot be found. I even turn off the firewall thinking it could be firewall settings but it still will not work.

Joe, and others with a problem with 3.6.4

Uninstall 3.6.4 Download 3.6.3 from here: http://download.mozilla.org/?product=firefox-3.6.3&os=win&lang=en-US

Install 3.6.3 (keeping your personal data, bookmarks, etc) When 3.6.3 installed and running, go to (Tools -> Options -> Advanced -> Update). To switch off auto update.

Then wait for those nice Firefox developers to understand and fix the problem we are having with 3.6.4

hi! same trouble here,once i've upgraded into 3.6.4,the page do not load,i've tried all the day to uninstall reinstall 3.6.3 which works perfectly into 3.6.4. and the same problem still continue ..i'm on a laptop xp 2OOO sp2..i've to notice that i do not have this problem on my home computer xp 2000 sp3,firefox 3.6.4.works correctly on it,once upgraded..

I have the same problem. After upgrading to 3.6.4, firefox hangs. I've watched the task manager, and the firefox process will consistantly stop after loading between 11-13 mg in RAM. The only recourse is to kill the process in the task manager.

One workaround I've found: when I disable my firewall, firefox will run fine. I'm running ESET Smart Security 3.0.695.

My machine is running XP with all the latest patches as of 6/26.

I have the same problem, add on check hang on e then all the pages stay on loading status, even with Firefox 3.6.6.

hi again everybody! i came here yesterday to report the problem with 3.6.4,now i've upgraded into 3.6.6 and the same problem still continue,but,after a numerous try,ive noticed that all versions works in safe mode and without add-ons,only very basic,i've seen that firefox have posted a note to say that all add-ons will work once they've been upgraded by their owners too..all my add-onss are downloaded from mozilla firefox persona homepage,so i'll return to my 3.6.3 until they've done it all,the basic homepage loaded doesn't match with my work ..thanx in advance for the job and help assistance.

Same problem here, Windows 7 64 bits, 2x30" screens. Firefox*32 is visible in Task Manager, but does not open any visible window Had to revert to 3.6.3, which works like a charm. Other option to get old versions of firefox:

http://www.oldapps.com/firefox.php

Does anybody know if a proper bug report has been filed?