Photo Stream causing Aperture to hang
Since yesterday I am having problem between Photo Stream and Aperture. I had Photo Stream turned on ever since it was available. Whenever I open Aperture now, I get the spinning beachball and Aperture isn't responding. I have tried leaving it running for an hour and it didn't recover. When I look at the CPU utilitization, 3 processes are taking up all CPU time - (1) Aperture, (2) distnoted agent, (3) ApplePhotoStreamDownloader. Since the latter 2 are related to iCloud and PhotoStream, I disabled Photo Stream in my iCloud Perference. Afterwards, Aperture worked perfectly. When I turned on Photo Stream again, the same problem reappears. I have tried resetting the Photo Stream and remove all pictures via icloud.com. It didn't solve the problem. I have also tried signing in and out of the iCloud on my Mac, and it was the same. I have also tried reparing and rebuilding the Aperture library.
In additino, I can repeat the same problem on iPhoto. That leads me to believe this is an iCloud/Photo Stream problem rather than an Aperture problem.
Has any of you experienced similar issue? Any fixes or troubleshooting tips can you recommend?
MacBook Pro, OS X Mountain Lion (10.8.2)