I just reported a bug to Adobe but wanted to pass it along in case it affects any of you.
Lately I've been starting projects on OSX in the office, and attempting to finish them on my PC at home. Every time I've had maddeningly long delays when changing focus away from After Effects and back, or when saving. The whole app freezes for around 60 seconds every time, even for very simple projects.
My gut kept telling me it must be linked footage, paths not lining up, etc. But the error persisted even with no imported footage items, just empty comps.
It turns out the culprit was an old render queue job. In the queue was a successful render completed by the Mac in the office which had been saved to \\10.0.0.1\share\file.mov. Removing that completed entry from the queue fixes the problem.
I guess After Effects decides to parse the list of completed render jobs' output paths every time you shift focus back, and will happily freeze for 60 seconds while it waits for a network timeout.
Anyway - I've reported to Adobe, but I wanted to share in case it helps any of you out of a bind.
Cheers!
Allen Ellis
(724) 316-5484