Apple uses its Mac App Store program as the means for providing not only third-party software, but also OS X system software and updates. When you choose Software Update from the Apple menu, the system will open the App Store, which will check the computer for all software purchased and managed through the store. However, in some instances the download doesn't complete and the program may even hang, showing a spinning pinwheel cursor. You may not even be able to restart your computer, which obviously can be frustrating to deal with.
There are a couple of approaches you can take to clearing the problem. First, force-quit the program (the rest of the system should still be responsive). Then:
- Clear the App Store updates folder
When updates are installed by the App Store, the updater packages are placed in the Macintosh HD/Library/Updates folder. If the files downloaded are somehow corrupted, then this may interfere with the App Store's ability to run them. Therefore, as a first step, try clearing the contents of this folder.
- Clear the App Store caches
In addition to the updates folder, the App Store program creates a couple of caching locations to store temporary files in when running its various routines. Problems with these caches may cause the App Store program to hang.
You can fix this by opening the Terminal and running the following command to reveal the caches folder that your account uses for various programs:
In the window that opens, locate any folders that begin with the name "com.apple.appstore" and remove them.
Next perform this same routine, but this time open the Temporary Items folder by running the following version of the same command:
- Perform a permissions fix
Since the software-updating routines in the Mac App Store require access to system resources, ensure the permissions setup for these resources is in an accessible state by running a permissions fix on the boot drive using Disk Utility. This can be done by selecting Macintosh HD in the sidebar of Disk Utility, and then clicking the Repair Permissions button in the program's First Aid tab.