Please also try these troubleshooting steps: https://support.mozilla.org/en-US/kb/firefox-takes-long-time-start-up

Since it takes a while to start up with Safe Mode, it may be an extension, hardware acceleration, or jit.

Already using "don't load tabs until opened" and a blank home page.

Pretty sure I'm NOT using "hardware acceleration" as a recommended solution to problems with Flash.

Its down to about 3 minutes of Not Responsive after dragging a tab to become a new window. I cleared out a lot of stuff recommended to solve one of the other numerous problems w/FF:

>Delete the extensions.* files (e.g. extensions.json, extensions.sqlite, extensions.ini) and compatibility.ini in the Firefox profile folder to reset the extensions registry.

If this hasn't helped then also delete possible addons.json and addons.sqlite files. >

When you start Firefix in safe mode, are there any problems?

NOTE; Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All of them.

Yea, where does the data go when I check the "compatibility issue" button? Is there a web page summarizing problems?

Possible Mal-Ware Scan For Macs {web link}

Just spend a couple hours, trying to restart & restore a session. Tried restoring in chunks. Seems like almost every chunk has something that causes FF to lock up, forever Not Responding.

And the mozilla.org tabs seem to be "on top" when FF locks up. Had one where I could not select the URL in the bar, nor change the tab to another, nor close the tab, nor the window. Just frozen. Once it even locked up my whole computer & I had to shut down via the Power switch.

FF needs to become "smarter" about Restoring. Only do a chunk of say 10 tabs at a time, and improve the error recognition & handling so it doesn't just spin forever. Sometimes it doesn't even show the spinner; just won't respond & Activity Monitor says its Not Responding. Can't tell if the Not Responding is due to an active but CPU stealing process that is proceeding, or a stuck process where I should Force Quit. Just have to let it go for 10 minutes before Force Quit.

Restore needs to have a popup window that tells me exactly what tab it is actively Restoring at the moment, and a timer showing how long it was been working on that Tab. And I need to be able to tell FF how long to try before abandoning that Tab. Abandoned tabs go into a menu for me to mess around with later.

Hi VerizonSucks, There is a window for restoring the previous session in about:sessionrestore. It has the crash message, but you can navigate to this page anytime to view the last session Firefox had.

However there are improvements made in the next version of Firefox, version 33. It is coming out tomorrow. Details on the improvement are in this blog post blog post.

There are also a new mechanism for backups in the profile folder: [sessionstore-backups/recovery.js]