I just had the same problem on two different Macs. I phoned AppleCare.
They know about the bug. They believe it impacts people who previously used MobileMe with Aperture (I did). My other half didn't have the upgrade problem, but my other half also didn't use Aperture with MobileMe.
I was fearful that, since it said a library upgrade was required, that it damaged my library. Turns out the library upgrade was fine and all photos were fine. The issue is a .plist file corruption, but that's very easy to fix.
The fix is:
Close all apps.
Hold the "alt" key on the keyboard and click the "Go" pull-down menu (in finder) which causes the "Library" folder to appear (the "Library" folder wont be in the list if you aren't holding down "alt".)
Pick the "Library" folder.
Navigate to the "Preferences" sub-folder (under Library)
Find the file named "com.apple.Aperture.plist" and drag it to the Desktop (you can drag it anywhere as loing as you get it out of the ~/Library/Preferences folder.
ALSO... if you have a "com.apple.Aperture.plist.lockfile" (and you probably will) then you need to drag that file out of the Preferences folder (e.g. drag it to the Desktop) as well.
NOW start Aperture.
You'll probably get a message that the last time you tried to run it, it kept crashing. Just click continue.
Since you've moved the preferences file, you will get a few prompts that you're not used to seeing (I think you get a screen offering to give you an overview/tutorial, you'll be asked if you want to use it when a camera is connected to the Mac, and you'll get a prompt asking if you want it to show you were photos were taken on a map (which requires an interaction with Apple which would send the GPS coordinates of all your photos to them.) Aperture will create a fresh .plist file (non-corrupt.)
After that, Aperture will work normally again.
Once you've verified that Aperture is working, you can delete the copy of the old (corrupt) .plist files that you sent to your desktop. Just drag them to the trash.
JUST deleting the plist seems to have worked fine for me, over several hours and restarts. So far. What causes the issue to reappear?
That will depend on the reason for the crash:
For example, for some posters the reason for the crash is a missing or outdated framework in the library, that is needed, when uploading to Facebook. Removing the preferences removes the Facebook account from Aperture's web preferences and stops Aperture trying to connect to Facebook. As soon as you add the account again, Aperture will crash again.
I had the same problem and phoned apple care too. I also had to delete the Photomatix Plugin. To do that read here:
I deleted the plist plugin as described above and opened a small Aperture Library sucesscfully, then deleted the Photomatix plugin. Then reopend my big library an after that i could repair my old database and Aperture opened normally. Also look at these supprt messages:
I was a MobileMe and Aperture user, too. I followed the suggestion to just trash Aperture 3.4, then reinstall an older version…working fine now. See <https://discussions.apple.com/message/19648600#19648600>.
I never used MobileMe, but the bug still hit me. I firmly believe this is a Facebook issue. Since deleting the plist-file worked for me. Further tested this by editing the plist file as suggested by thom_ek Aperture will open fine with the edited plist.
BTW you may need to convert your plist for editing by using a terminal command:
plutil -convert xml1 [Drag in your plist here and hit enter]
Although I did disable Facebook in system preferences before deleting the plist file, re-enabling it did not cause any problems. So my belief is that the issue is in the plist-file.
Got a way to fix this from Apple Support. I had posted the problem to feedback. Received an e-mail from David.
Here are the steps David recommended to me. They seem, to have worked.
Delete Aperture App
Download trial version from here Aperture 3.1 Trial
Download 3.4 update from here http://support.apple.com/downloads/#aperture
When I opened Aperture, it repaired the library. Seems to be okay now.
Aperture is working fine for me after removing the com.apple.Aperture.plist from my user/Library/Preferences/ I posted earlier, but when trying to use Facebook, it continues to crash.
Now I am wondering, no matter what fix you used, for those who use Facebook via Aperture 3.4, is there anyone that is able to use it without crashing a single time? If yes, please explain, what you did to resolve the issue.
I bought Aperture 3 on a DVD (not on the App Store), but don't have it with me right now, as I am on a business trip overseas. I do have my serial on file. (I will have access to my DVD in a week from now again, but am hoping to fix this problem quicker).
I bought Aperture 3 on a DVD (not on the App Store), but don't have it with me right now,
You do not need your DVD, to try the fix Stan described:
Download the Aperture 3.1 Trial installer ( Aperture 3.1 Trial) and then upgrade again immediately, before launching Aperture.