Ω Sharing an Aperture 3 Library Among Multiple Users on the Same Mac

The Background

Our family shares an iMac and an iTunes library using one family user account. We use this account to sync all of our iDevices with music, apps and photos. Members of the family have individual accounts, and none of these accounts has access to the shared iTunes library, and that’s the way we want it.

I wanted each user to be able to access and edit the Aperture 3 library so that we each could drop E-mailed pictures into it (directly from Mail), edit pictures and share photos via E-mail (directly from Aperture). The “obvious” (but incomplete) solution is to move the family’s Aperture library from our shared account to the /Users/Shared folder and hold down option while launching Aperture to point to the Aperture library in the Shared folder.

Aperture gripes about the relocated library because the library has the file permissions (owner, etc.) of the shared account, and each user can’t do anything to it. Solutions tried by others include using Finder to add permissions for each user (via Get Info), changing group permissions (also via Get Info), and various command line incantations, none of which purport to be 100% successful, and none of which worked for me. The only solution which works, according to a long search of the Intarwebs, is to attach a second drive (or create a partition) and tell the Mac OS to ignore permissions on that drive. Without a second drive and without enough room to create a large enough partition, this option was out for me. Only in one place did I find somebody who claimed to have performed some command line fu which did the equivalent of ignoring permissions.

But that was enough for me to venture down into the depths of ACLs (Access Control Lists) to make this work.

The Warnings

Note that although I have tested the solution on my own Mac, I do not guarantee that it will work for you. You should… no, that’s not strong enough. You must backup your Aperture library before trying any of these instructions.

Even though the result of these instructions should be a shared Aperture library, only one user may access the library at a time, and Aperture 3 will gripe if more than one user tries to access it simultaneously.

Finally, if any of this makes you uncomfortable and you are uncomfortable with the steps below, don’t try them and just live with an unshared library. Hopefully, Apple will do something about library sharing in the future, and you probably can deal with the inconvenience until then.

The Solution

Step 1: Close Aperture.

Step 2: Move the shared Aperture library to the /Users/Shared folder, as you might expect. Any of the users can provide the source library as far as I am aware.

Step 3: Open Terminal and change directories to /Users/Shared.

Step 4: Execute the following command line fu for each user who is to share the Aperture library.

sudo chmod -R +a "user:username* allow list,add_file,search,add_subdirectory,delete_child,readattr,writeattr,readextattr,writeextattr,readsecurity,file_inherit,directory_inherit" Aperture\ Library.aplibrary

substituting the appropriate short username in for username above, and of course it’s all one line. (Spaces are not allowed in the ACL either, by the way.)

Step 5: Test the installation by opening the library (hold down option when you start Aperture to select the newly-shared library) in each user’s account. I tested the installation by adding a photo from each user’s account, making sure all other users could see and edit the photo, and ensuring that all other users could see the resulting changes.

Step 6: Put an alias to the shared library into each user’s Pictures folder so that iTunes will know where to look for the shared library. iTunes seems to be able to follow the alias nicely.

That worked for me and, as the saying goes, your mileage may vary, so please let me know if you have anything to add or encounter problems. Please don’t hesitate to contact me using the contact E-mail address buried over there under “Who is this Bill guy, anyway?”