How to solve iOS 4.3 syncing issues
If you're having issues syncing your iPhone, iPad or iPod touch after updating it to iOS 4.3, this tip is for you. It turns out that many people have seen a bug where, after updating any iDevice to the latest version of iOS, syncing with iTunes will stall at step four of four on syncing photos. The stalling is accompanied by a message that the sync could not be completed because "the required file cannot be found". Does this sound familiar?
Well, it turns out that the solution to this bug, that apparently keeps intermittently appearing, is quite simple -- if rather time-consuming. The culprit for this particular issue is your photo library. And the way to fix it is to uncheck photo syncing in iTunes, then sync. Afterwards, check photo syncing, and sync again. This will cause the second sync to take a long while if you have many photos in your library, since iTunes needs to re-optimize your photos and copy them back to your iDevice. However, it does work.