My iPhone stops syncing at step 2 in the iTunes sync process, and I’m not sure what to do. I have tried restarting both the iMac and iPhone with no joy. I have also reinstalled iTunes on my iMac but nothing helped. What can I do?
As long as both the iTunes and the iOS are updated, there shouldn't be any issues. This problem may be solved by restoring your phone to factory settings. However, you may lose your data. One thing you could do is to create a back up of your phone before restoring. If none of this works, a short visit to the apple store should be useful since they'll help you fix the issue even if you're not under a warranty. Just be sure that your phone is not jailbroken (which could also be causing the problem).
Have you updated to the latest iTunes?
upgraded to iOS 6 and now I can't sync my phone
Depending on how old your last backup is you could try to simply reset to factory and then restore form a backup. You can check the date either on the iPhone page within iTunes or by going into Preferences > Devices
You could also try to deselect all data from being synced and reselect them one by one. This way you can rule out or find any App or other data that may cause issues.
On certain occasions people suggest to try (re)moving all previous iTunes backups:
go into ~/Library/Application Support/MobileSync/Backup/
Move all the contents to a temporary folder e.g. on the Desktop and try syncing again.
General tipps for syncing issues:
Repair Permissions on your hard drive using Disk Utility
make sure iTunes is up to date
make sure you have free RAM and your system isn't busy (see Activity Monitor)
try another USB port
try another Docking cable