Ever since updating my iPhone to iOS 5, I was unable to complete a sync.
It backed up fine (thankfully), it did the majority of the syncing, it just got to the last ‘stage’ of the process and hung there perpetually. I saw messages such as “Waiting for items to copy”, “Waiting for changes to be applied” and so on.
It wasn’t a complete showstopper, since I could sync the majority of content, make sure I was backed up, and then just cancel the sync at the last stage, but it was something that needed a fix.
I get the impression that this symptom is caused by various syncing issues and that some solutions have worked for some people, and not for others. Bear this in mind — this solution worked for me, but it might not work in every case. 🙁
I believe I have now solved this problem on my iPhone.
Delete All Copies of Voice Memos
I deleted all of the synced Voice Memos in my iTunes library, then also went into the Voice Memos app on the iPhone and deleted each and every one there. Upon the next sync, the locking up at “Waiting for items to copy” did not happen, and the sync completed successfully.
This suggests that one of the causes for this issue is Voice Memos. If you are experiencing this issue, try backing up and removing all the Voice Memos from iTunes, removing them all from the Voice Memos app on the iPhone itself, then syncing again.
(The iPhone does still sync Genius Data each time it syncs, but this does complete successfully. Perhaps this is normal — I am not really sure!)