When I'm trying to drag a new file (video, picture, music, any file, it doesn't matter) into the timeline — pop-up message «Saving project» appears for a millisecond — then nothing, AE just freeze and «Not responding» after that. Sometimes, not always, restarting a computer can help, but, you know, this is not a good way to work with. There was no problem like this on my mac several days ago. Full reinstall with cache cleaning using Adobe cleaning tool and other apps like Appcleaner doesn't help.
Software and hardware info: After effects CC 2014 (18.104.22.168) installed from Creative cloud: clean, new, updated, without any plugins or add-ons. Other Adobe apps like Ps or Ai are running well on a Macbook air 13" mid-2012 (intel hd 4000, intel core i5, 4GB memory) with OS X Yosemite.
I captured a short video with a problem demonstration: