Aperture: Thumbnails in browser are sometimes gray

Resolution

This can happen if you copy your Aperture library to a read-only medium, such as a DVD-R or CD-R. When you copy it back to a hard drive, the permissions can be altered in such a way that the thumbnails can no longer be properly accessed.

If you plan to copy your Aperture library to a read-only medium, you can avoid this issue by compressing the library before you copy it to the DVD-R or CD-R. To compress the Aperture library, control-click it, and choose Compress "yourlibraryname" from the shortcut menu.

If you find that you have an Aperture library that exhibits this issue, here's a procedure that may help:

1. Quit Aperture and locate the library on your computer. The default location is ~/Pictures/Aperture Library, but if you have moved or renamed the library, it may be elsewhere.
2. Control-click the library, and choose Show Package Contents. A Finder window will open.
3. You will see a package for each of your projects, named projectname.approject. Control-click the first project, and choose Show Package Contents.
4. In the resulting Finder window, locate the files AP.minies, AP.Thumbnails, and AP.Tinies.
5. Control-click on each of these three files, and choose Get Info.
6. In the Info window, open the disclosure triangle for Sharing & Permissions.
7. Click the lock icon at the bottom right of the window, and authenticate with an administrator name and password.
8. Set the permissions for your user to "Read & Write", for staff to "Read Only" and everyone to "Read Only".
9. Repeat steps 3-8 for each project in your library.
10. Close all the open windows, and open Aperture.
11. Choose the first project in the Project Panel, and select all the images.
12. Choose Images > Generate Thumbnails.
13. Repeat steps 11-12 for each project.