I'm looking for advice on the migration of my Aperture 3 library to a new iMac.
To move an Aperture library to a new mac do this:
- Make sure the library has no problems by running the Library First Aid Tools on the library: Repair the permissions and repair the library. See: Repairing and Rebuilding Your Aperture Library: Aperture 3 User Manual
- Make a backup before moving everything.
- Then log into your account on your new mac and copy the library over, either using the network, if the library is small, or connecting the two macs in Target Disk Mode: (OS X Lion: Transfer files between two computers using target disk mode), or, if the library is large use a sneaker drive: copy the library to an external drive formatted MacOS X Extended (Journaled) and use that to transfer the library to your new mac.
Then connect your drive with the referenced images to your new mac, double click the Aperture library in its new location and once again run "Repair Permissions".
Check, if Aperture on the new mac can see the referenced images on your external drive.
If yes, you are done. If not, see: Aperture 3 User Manual: Working with Referenced Images; the paragraph on Reconnecting Missing or Offline Referenced Images
. For quite a while now (better part of a year) and have to force the regeneration of all previews. I connect my Panasonic Lumix DMC-TS2 or my Canon 70D and the import pane shows all the images. Once the import begins, each preview disapears as the import progresses. All previews are black by the time the import ends. I always have to force the "Generate Previews" on all the images.
I suspect, this could be caused by the problem mentioned above "Sometimes I forget to turn on the external drive and sometimes it is slow to mount"; if the drive is seen as offline by Aperture, it will fail to generate the previews. Have you run a disk check on that drive?