Error message when attempting to sync via USB
The iphone'Name' cannot be synched. An unknown error occurred (-54)
iPhone 6, iOS 9.1
User profile for user:
jeremy_v
User level:
Community Specialist
Hi crooga55,
Thank you for visiting Apple Support Communities.
If your iPhone can't be synced due to an unknown error, I recommend going through Resolve iOS update and restore errors in iTunes.
The steps in this guide can help with your situation even though it's directed towards update and restore errors.
Sincerely.