Yes, it's iOS and we always run our tests in a simulator.

Ah, that was the issue - I grabbed the session off the App instead of a view. Moving it down to a view solves the issue. Thanks!

Thanks. Yeah, that's pretty much what I thought was going on. I've spent a bunch of time combing through my code and the memory graph, converting lots of reference to weak, but the leak remains. One thing that confuses me is when I see an object in the memory graph (such as a view controller) where all of the references to it are "conservative", which seems to mean "weak". If they're all weak, why does the object remain?