Aperture Vault - is it safe to delete stuff from my library?

NO!

If you delete them from Aperture then the next time you update the vault, they will be removed from the vault too.

The way I archive older/unwanted stuff is to CTRL+Click the project and use "Export->Project as New Library" (if you are happy keeping your images with the referenced images, don't check the box to copy the originals - so you are just saving your projects metadata and edits). This creates a new small library for just that project.

Once you have a copy you can delete the project from Aperture (and it will be removed from the vault during the next update).

Note 1, one copy of something is not a backup. One copy means it's the only copy so these projects should also be backed up somewhere like the rest of your data.

Note 2, referenced image files are not backed up in the vault, so you need to be backing up your images seperately.

Andy

What I don't altogether understand, though, is what the purpose of the vault is, if everything is deleted from it if you delete from the library. Why not just do as you suggest, and make a copy of the library on another disk in order to create backups?

Mandy, vaults are incremental backups. Copying a large Aperture library for backup may take a very long time. The vault will save time by updating your current vault and only writing the changes to it. This is much faster.

If you want an archival backup - to save a snapshot of your current library, then don't update your vault after changing the library, but keep the old vault and start a new vault. You could create a new vault after each major change to your library. You may have as many vaults as you like, to backup the history of your vault.

But frankly, I prefer to simply backup the original image files, directly before importing them to Aperture, and then backing up the Aperture library with Time Machine and to keep two additional copies of the Aperture library on separate drive. But I never delete projects from the Aperture library that I want to keep. My Aperture library has all my photos - I try to save space by rigorously deleting single photos that are technically bad, boring, or redundant.

The ability to export as Libraries only came in in version 3, back in version 2 they were exported as projects which wasn't quite as useful. Also iPhoto now reading Aperture libraries adds a bit more convenience.

I've not used vaults for a while, since way back in early version 2. I can't confirm it still does this now, but at the time it didn't store thumbnails and previews for secondary and multiple versions in the vault, only the master version. So if you used a lot of versions it meant the vault could be much smaller than the library.

So back then vaults seemed a good idea, but in one Aperture version it started taking ages to process the vault updates so I gave up on them.

I use referenced masters and am very selective about which images get previews so my library is very small, which with USB 3 means it's easy and quick to make ad-hoc backups, and I also let time machine back it up over wifi.

For my referenced images, I backup using software called SyncTwoFolders which also lets me keep deleted images around for a while and do a few other tricks. For example, periodically I verify the integrity of my backup by using locate referenced files and pointing it at my backup drive and forcing a reconnect to the backup instead of the main. When it's done, I can then check for missing files in Aperture to see if my backup has any gaps. I also like to move things around from time to time, just to give me confidence I know where everything is and I haven't created too many strays.

It's much easier and quicker than vaults and at this time, I can't think of a single advantage of vaults (for me). But obviously a vault is a million times better than no backup!!

Andy