I’ve been seeing a curious set of errors in iTunes lately. One of the symptoms is that iTunes would ask me for to login to my iTunes Store account at random times. After I entered my user id and password, it would ask for them again and then take me to the user account screen in the Store. It was also forgetting which podcasts I had selected to be automatically synched to me iPhone. Annoying but not a fatal flaw. However, a more serious symptom cropped up yesterday.
The App Store told me that there was an updated version of EA Sports’ Madden Football game for the iPhone, but when I tried to download, I got a message that the Store was unavailable now and to try later. As you might guess, it didn’t matter if I tried later, still the same message. Then today, I wanted to download a new app from the store and got this message: “An unknown error has occurred. (-9809)”. I did some searching online and the only references I found in Apple’s support forums was to people using iTunes on Windows Vista. Not helpful for me.
So I looked in OS X’s Console.app to see if there were any telltale indicators of the problem cropping up there, but there was nothing. I thought the problem might be in OS X’s Keychain, so I opened it up and ran Keychain First Aid, but no problems there either. So I resorted to basic troubleshooting techniques: Erase caches and preferences and if that doesn’t work, delete and reinstall.
I quit iTunes and then found the caches for iTunes in the Home folder (the folder inside the Users folder that likely has your name on it). The exact location is (Home)/Library/Caches/com.apple.iTunes/. Inside the com.apple.iTunes folder was two files, cache.db (which was 159mb!) and goog-phish-shavar.dat (only 262k). No idea what the latter file is, but if it’s in caches, it’s toast. I deleted both and, presto!, iTunes was working fine again.
Bottom line: If you get error -9809 in iTunes on Mac OS X, delete the cache files in (Home)/Library/Caches/com.apple.iTunes/, and try again.