User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_4; en-us) AppleWebKit/533.16 (KHTML, like Gecko) Version/5.0 Safari/533.16 Build Identifier: Using Firefox 3.6.6 and Mac OS 10.6.4. Suddenly Firefox doesn't start up. I used Firefox the whole morning. I shut off my computer. And now, when starting my computer again.......Firefox shows this problem. When clicked, the icon in the dock bounces up and down and then stops bouncing after 5-6 seconds. When I click the Firefox app in the App Folder....same problem. I CHANGED NOTHING......no settings, had no downloads.......absolutely nothing. I used Disk utility to repair disk permissions. I restarted my MacBook Pro several times. To no avail. I now use Safari to get to this site. Reproducible: Always
Do you already tried http://support.mozilla.com/en-US/kb/Safe+Mode ?
looks like op is not here around, if you can reproduce, feel free to reopen it!