Aperture 3.4: May quit unexpectedly on launch after updating

Resolution

Reinstall Aperture to resolve this issue. 

Note: Reinstalling Aperture will not affect your photo library.

If you purchased Aperture from the Mac App Store:

1. Go to the Applications folder and delete Aperture.
2. Open the App Store application.
3. Be sure you're signed in to the App Store with the Apple ID you used to purchase Aperture. Choose Store > Sign In to change accounts.
4. Choose Store > Purchases to bring up a list of your purchased apps.
5. Click the Install button to the right of Aperture.

If you originally installed Aperture from DVD media:

1. Go to the Applications folder and delete Aperture.
2. Insert the Aperture 3 install DVD.
3. Double-click the Install Aperture package on the disc.
4. Follow the onscreen instructions to install Aperture.
5. After the installation completes, choose Software Update from the Apple () menu.
6. Install the Aperture 3.4 update from the list of available updates.

If you originally installed Aperture 3 from a trial version:

1. Go to the Applications folder and delete Aperture.
2. Download the Aperture 3.1 Trial.
3. Open the Aperture Trial disc image.
4. Double-click the "Aperture Trial.mpkg" file.
5. Follow the onscreen instructions to install Aperture.
6. After the installation completes, choose Software Update from the Apple () menu.
7. Install the Aperture 3.4 update from the list of available updates.

Note: If you are using OS X Mountain Lion v10.8.2 or later, you may receive an alert stating that Aperture is from an unidentified developer. This can occur when you try to install Aperture from DVD or the trial download. See OS X Mountain Lion: The app is from an unidentified developer for details on how to successfully install Aperture in this situation.