[Ken Case]

Originally Posted by dnaunton

I was the good people at OmniFocus Support who suggested the Security Update as a possible issue!

That's just our support ninjas reporting on the latest speculation from the forum thread which discussed these permission problems: http://forums.omnigroup.com/showthread.php?t=5777.

I applied the security update and had no problems, and as I read through the discussions.apple.com thread it doesn't sound like that's talking about quite the same issue (since that thread talks about access control list entries getting mistakenly propagated, not about ownership changes).

So, unfortunately, I don't think we've truly figured out the problem yet.