I'm using AE CS5 and have run every update that Updater has told me to run. I'm on OSX 10.6.4, a Mac Pro 1,1 with 6GB of RAM, running only AE usually, but a system which also has Final Cut Studio and Avid Media Composer installed, with all their respective codecs and extensions.
I get a spinning beach ball hang nearly every time I create or rename a layer, for example a new solid, null layer, etc. It also happens sometimes when copying layers. Granted it's a relatively large project which takes a good 8 or 10 seconds to open at launch.
Anyone else seen this? I'm considering going back to CS4.
No idea, but I suspect it might be OpenGL related. therefore as a first try to turn it off.