Just successfully updated iTunes and IOS. IOS 6 now on iPhone 3GS. However, repeated 'failure to sync, error 1156'. What does this mean? What is the remedy?
Solved it! The move to new iTunes and new IOS clearly has a few settling issues.
1. Sign-out of iTunes Store
2. Disconnect iPhone and switch off 'sync over wifi'
3. Close iTunes
4. Shutdown and cold re-start computer
5. Start iTunes
6. Dock iPhone and allow sync to take as long as needed (10 mins+ for me)
7. Force new sync and watch steps flow through
8. Sign-in to iTunes Store
9. Turn on iTunes Match
Complete ... fully working iTunes and IOS!