The iPad/iPhone cannot be synced. An unknown error occurred (1156), fix

Several users have reported that they are receiving the following error message when they try to sync their devices:

The iPad (or iPhone) cannot be synced. An unknown error occurred (1156).

To try to solve this issue, try the following steps:

1. Disconnect your device and turn off “sync over Wi-Fi” by tapping Settings > General > iTunes Wi-Fi sync
2. Restart your computer and your iOS device
3. Reinitiate your sync process

Note: Make sure that your have the latest iTunes version installed.

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