Sync iPhone/iPad with iTunes after library rebuild

In researching solutions, I found this discussion at apple.com in which somebody suggests "damaging" the iTunes library. This lead to a very useful post which discusses how iTunes uses the data it has to recreate what it doesn't have and gives instructions on how to damage (without deleting) the file -- spoiler: erase the data, leave the file.

Fortunately, I had backed up the iTunes files before I recreated the iTunes library.

I copied my backed up files back into the iTunes directory and launched iTunes and rebuilt what it needed to. There were no apps listed in the Apps display though.

When I connected my iPad, iTunes didn't complain about this being an unknown device. As it started to sync, it prompted my to transfer purchases (i.e. the apps on my iPad which didn't show in iTunes) -- but with no hint of having to erase anything. The sync took longer than normal, but everything is there and I can even find the songs which were originally hidden.

iPad is fine, will sync my wife's iPhone tonight.

The one thing you need to watch out for is any app data that isn't backed up. When iTunes erases an iDevice, it doesn't mess around. It deletes everything. If you plug in and sync often, it backs up your data and you can restore from that backup.

All purchases on the App Store are available for re-download so you won't lose anything in just erasing the devices and re-syncing.

You can pull the images off with iPhoto, which is a really cool app! It's great for rescuing photos, but also for general organization.