iPhone users are reporting a significant new problem involving iPhone syncing through iTunes after the iPhone OS 2.2.1 update. Posters to a thread on Apple's discussion boards report that afflicted iPhones will sync with iTunes for a period of time before stopping completely, generally after deleting songs. User "Scott" writes:
"My issue seemed to be triggered by attempting to delete some songs on my iPhone. Delete seemed to be progressing until iTunes hung (spinning beach ball) and finally crashed/quit. "Submit error report to Apple" dialog appeared and I have been submitting them pretty much each time it happens. Looking at iPhone, songs in question appeared to still be there, but interestingly album art was replaced by completely unrelated podcast album art. Song track times listed correctly, but when played it just skipped through each track in a second. So some corruption occurred at some point that might have triggered all this. After restoring, no apps will fully sync (if you select just one app, it will appear to install until nearly done, then iTunes crashes). No music will copy without triggering a crash. Interestingly, personal data (contacts, texts, etc) for built-in apps restored fine."
In addition to deletion of music, the problem may affect deletion of other media, as well as applications. Whatever the case, users report that typical fixes do not help. Some of these users are left with only the basic apps that come with their iPhones. One user, "Keven-77," wrote:
"I just noticed something. I set iTunes to NOT automatically sync my iPhone. Then in the Music tab I chose to sync 'Selected playlists' and started off by just turning on one playlist at a time. After some would sync and others crashed I noticed that it seemed to be the playlists that contained files that were 'Protected AAC audio file' were the ones that caused iTunes to crash. So, I just made a smart playlist that doesn't include any Protected AAC audio files (as well as video files) and it seems to be syncing everything so far.
Some users have, however, reported success with performing a full restore and/or re-installing iTunes. If you would like to attempt a restore, follow this article. You can download and reinstall iTunes from here.
As aforementioned, some users report that DRM content is at the heart of the problem, though that cause is not universal. So far, Apple is keeping mum on the issue, and no official fix has been suggested.