“We’re looking into a small number of reports that some iPad units are receiving an error when updating the software,” an Apple spokesperson told iMore. “Those unable to restore their device through iTunes should contact Apple support.”
The ‘Error 56’ support document on Apple’s website points to this being a hardware issue, though its clear here that Apple engineers messed something up with the iOS 9.3.2 update that has led to perfectly working iPad Pros to display this error.
It remains unclear for now what Apple is recommending customers who are contacting their support team do. Most customers are reporting that Apple has set up a Genius Bar appointment with the affected customers who reported about the problem.