Deleted album: restore from backup?

Easy to do.

Double click on the backup Aperture library and export the album (in its entirety). Then quit Aperture, double click on your main library and import it. This should be a 5 minute deal; a full clone of the library is a really good idea, so good on you for that 😉

AFAIK, there is no export album, you'll have to export the project that contains the album, then import it into the current version of the library. I guess this might give you some duplicates, that you'll have to merge/dispense with manually.

Deleting an Album doesn't delete it's contents, in the same way that deleting a playlist in iTunes doesn't delete the music files.

Only deleting a Project will delete the files - you should find all the images untouched in their original Project(s), probably all in the Project that contained the Album.

All you should need to do is make a new Album with the same name and add the images to it from the Project(s), unless something else has gone wrong there should be no need to go to a backup Library or Vault.

Obviously if it's a 'special' Album such as a Lightbox, Web Gallery or Book it's different as you'll have lost all the layout stuff.

Ian