I wanted this information because I had a problem upgrading iPhoto to 9.4.3 and not even the Genious Bar™ was able to make it update. It was suggested I may need to reinstall Mac OS entirely. If I was going to have to do that, which would take days as I use a lot of large proprietary software implementations such as Adobe Creative Suite which would also have to be deactivated, reinstalled and reactivated, I decided to try to fix it myself. So I checked my Time Machine backup, turned off Time Machine and had a poke around on my disk. I know that Apple prefers we don't look at our filesystems this way, however, it has been maintained in many court decisions that the contents of our hard drives are ours to do with as we please. USE THIS INFORMATION AT YOUR OWN RISK. IT'S MORE LIKELY THAT THIS INFORMATION WILL HELP YOU HELP A TECHNICIAN SOLVE THE PROBLEM THAN FIXING IT YOURSELF WITHOUT A KNOWLEDGE OF BSD AND UNIX.
I know it's been a while, however, there is better information available about App Store download locations, this information should be handled very carefully as you'll be viewing areas of your filesystem that are not considered ‘end-user friendly’.
For instance, I had a problem with my Internet connection and received a corrupted PKG for my iPhoto 9.4.3 update. The update refused to install even after I uninstalled iPhoto and asked it to reinstall.
I viewed my Console when attempting to upgrade iPhoto and saw that it was attempting to access a PKG file called:
from a Console system message entry that looked like:
26/06/13 12:34:39.041 PM App Store: PKDistributionController: Found asset mzpsxxxx03867858650xxxx.pkg on disk for item 4xxxxxx1 - Size 2xxxxxx2
Upon searching my filesystem with a command in terminal, I discovered that the corrupted PKG file was located at:
This location is likely to be referenced by an internal OS database, and I basically just had to hope that removing the file would allow the database to clear the entry and force the PKG file to download again.
I deleted the file and restarted, asked iPhoto to install in the App Store, and everything went smoothly. After 20 or so other attempts, following Apple's support info, and asking colleagues, this was the ONLY solution to the problem without completely reinstalling Mac OS.
It's interesting that we don't find much information about these storage locations or information about solving App Store problems when PKG files get corrupted during transfer or installation, it's likely that Apple scrubs this information from the Apple Support Communities and I'll be curious to see how long this post lasts on the site.