Currently Being ModeratedJul 10, 2012 6:26 AM (in response to Mark Duehmig)
That's a big Library. If you force-quit, you should then repair your Library, which will take at least a few hours anyway. I'd let it run for six hours, and see if it reports any change. It is (unfortunately) not uncommon for Aperture to give no sign of working, even though it is. OS X's Activity Monitor will often report "Not responding" -- which, presumably, is correct, but doesn't confirm that it is hung. Perhaps someone with more knowledge can tell you whether an actual hang will show in the Console.
As a couple of reference points, upgrading a Library with only 50K Masters (but 1 TB of data) was done overnight. Upgrading a Library with several hundred thousand Masters (but less than 500 GB of data) took over 100 hours. Those numbers are from a MBP 5,5, 2.3 GHz, 8 GB RAM.
Currently Being ModeratedJul 10, 2012 1:04 PM (in response to Kirby Krieger)
After five hours, still on 0%, I force quit Aperture, and ended up having to restart. Finder crashed too. When I relaunched I ran the library rebuild utility (holding down command + Option while launching Aperture) and chose Repair Library. The first thing it said was that the library had to be updated. So the repair also updated it and now it is open and fine.
Thanks for your help Kirby!