Comment 8 for bug 528139

Micah - Thanks! That launched, kept prefs, bookmarks, etc. With the disabled extensions page, it showed "2 new add-ons have been installed."

-In the dpkg listing, the first adblock-plus listing is a dummy package.
$ dpkg-query -l adblock-plus xul-ext-adblock-plus
...
ii adblock-plus 1.1.3-1 transitional dummy package
ii xul-ext-adblock-plus 1.1.3-1 Advertisement blocking extension for web browsers
... (guess I'll remove the transition package)
I then restarted firefox again (now all extensions off thanks to safe-mode toggle), then enabled extensions; With all the ones I had running prior to 3.6 re-enabled, it's working fine. So I have no idea what/how the profile was corrupted/damaged (or ??) in the 3.6 update (assuming), but it's working now with restore = safe-mode to turn off extensions for first startup... Thanks for your help on getting my firefox running again.