I understand that if I want to delete all previews, and not have them regenerate every time I start Aperture, I need to set up that preference for every existing project that i have.  The guidance I’ve seen indicates that the way to do this is by going to the gear box (located on the bottom right hand side of the Library tab) and look for the Previews tools.  On my version of Aperture (3.4.5), however, the only thing the gear box lets me do is “Add Vault”, “Remove Vault”, “Undo Vault Path”, “Update Vault” and “Restore Library”.  Does anyone have any idea why this is the case, or where I should be looking to suppress previews for existing projects?

I’ve already set my Preferences so that new projects do not automatically generate previews.

Thanks!!!