A while ago, I posted a blog about previews, discussing when they’re useful and how to turn them off. A friend of mine, Ralph Hill, recently told me about a potential problem when you disable previews, and it’s worth sharing with everyone.
Specifically, if you turn off previews, quit, but do NOT force quit, Aperture as soon as possible after changing your settings (if Aperture crashes before you quit it normally, that counts as an accidental force quit). It is possible if you force quit Aperture that you will end up in a funky state where the preference for preview generation displays that generation is off, but Aperture is still creating previews (try saying that three times fast! :) ). If you do happen to end up in this state, simply turn previews back on, quit Aperture, re-open Aperture, turn previews off, and quit Aperture again to restore everything to the correct state.
Lastly, to all of our American readers, Happy Thanksgiving!