First, a timeline of events: Using iPhone 3GS, updated iTunes and iPhoto to most recent version (and I have double checked that they are), synced 3GS twice before my new 4S was delivered on the 14th. New sim card, 4S activated, 3GS deactivated, returned 3GS to factory settings. I then set the 4S up and all seemed well. Then I plugged it back into iTunes and commenced syncing my music onto it. Despite numerous attempts, each time I set it up and left it, I would return to find iTunes saying it had finished the sync, but no music actually having been copied. The 4S would appear to still be syncing though, with the little spinning "sync" icon showing. This continued to spin when iTunes was closed, the phone was unplugged and no wifi was involved. In order to stop the "sync" I had to restart my iPhone. The music I was attempting to sync was exactly the same as that which had been on my 3GS hours before. After each attempt I returned the 4S to factory settings. On the next occasion I remained in the room while it synced. My (new) iMac began the sync and then turned off the screen to save energy. I double checked (wiggled the mouse) to confirm it was still syncing. It was. The second time the screen turned off I ignored it. Then the iMac HDD span down. I assumed it was finished. It hadn't. iTunes was hanging. When I attempted to re-sync, iTunes told me that the 4S had 32GB of "other" on it (which I know refers often to data left behind by failed syncs). Returned to factory settings again. This next time I watched the whole sync, wiggling the mouse every 2 minutes. Finally, the music managed to copy. I observed that iTunes had inserted several steps into the sync process. It had been: "Backing up" > "Syncing email" > "Determining tracks" > "Copying tracks" > "Copying photos" This had changed to: "waiting to sync" > "Backing up" > "Syncing email" > "Determining tracks" > "Copying tracks" > "Copying photos" > "waiting to copy data" > "Copying Genius data" > "waiting to copy data" > "Copying photos" > "Finishing sync" (I notice someone else has queried what the "Genius data" step involves) I then tried to sync the photos. The first time I set them all to go in one big lump. This screwed the phone up again and I had to restore it to factory settings all over again. Tried again, synced music and then synced photos in batches of about 1500 (I have a lot of photos). Photos were copied successfully about 20% of the time. Each time data was successfully copied the "waiting to sync", "waiting to copy data" and "finishing syncs" hung for about 3 to 5 minutes *each* (measured with a stopwatch). The other 80% hung at one of these steps for times in excess of 7 minutes, at which point I gave up and attempted to cancel the sync. When I did, the "cancelling sync" hung for about 7 minutes. I then gave up and was forced to unplug the phone and restart it. At this point in time, I have managed to copy the larger part of my photo library across however, now it refuses to copy *any* data at all. I tried to delete all the photos off to start again without restoring to factory settings but the sync just hangs at the "waiting to sync" stage. I have tried forcing it to start syncing again by changing the data to be synced, but this doesn't achieve anything other than causing it to start hanging all over again. The photos, just like the music, is exactly the same as that which had been on my 3GS, only now I have a larger capacity phone. (64GB from 32GB). So, questions: Why are all these new steps added to syncing and what do they do? Why do these steps take so long? Why, when these steps take so long, does my iMac believe the HDD is not being accessed and spins them down? More importantly, why, when any photos are introduced, does the 4S freak out? Is this a software issue (iOS5) or is this hardware? Does anyone else have this or a similar issue? It might be an issue with this particular piece of hardware, in which case, I'll need to get a replacement 4S Note: Despite it being an issue with music and photos, I'm going to restore the thing to factory settings (again!), rebuild my iPhoto library, remove the old iPhone folders from the iPhoto package and start again. I will update if this solves anything.