Currently Being ModeratedJun 10, 2013 12:44 AM (in response to sataguler)
Does this stop, if you launch Aperture by double-clicking the Aperture icon while holding the Shift-key down (to defer the generation of previews)? And when you try to work with a new, empty test library?
Then you probably have imported an image or video, that Aperture cannot process. Aperture will try over and over again on each new lauch to render previews for this file. So you need to find the file that makes Aperture get stuck and remove it from the library.
Check the files you imported into Aperture, when the problem started. One way to do it, is to launch Aperture with the Shift-key and to create previews manually (Photos < Update/Generate Preview). If this causes the spin, you have found the culprit.
For a systematic search, see my User Tip here:
Currently Being ModeratedJun 10, 2013 2:34 AM (in response to sataguler)
I looked for the corrupted files, but found none. Whatelse can I do?
Very often it are older videos, that suddenly are causing problems.
Try again to launch Aperture without Shift-key, and open the "Activity Window".
When you see that Aperture is hanging, select the current task and press the "Pause Task" button. You should now be able to see the filename in the panel.
Check this file.