On Monday, Apple rolled out version 9.3.2 of its mobile operating system to fix a small number of bugs. But the update itself has introduced a bug of its own -- one that affects the iPad Pro.
Users chiming in on MacRumors support forums, on Apple Support Communities and on Twitter say the new version has bricked their 9. Pro tablets, meaning the device locks up after the update is installed and won't restart.
Many of those hit by the glitch say they receive an "Error 56" message that tells them to plug their device into iTunes. But that action does nothing to resolve the error, and rebooting simply returns the device to the same state.
New versions of software such as Apple's mobile operating system undergo heavy internal testing. But they may still introduce bugs that appear once the final release is downloaded by millions of people. These glitches frustrate users and raise doubts about a company's ability to fully vet its own software. Apple has bumped into a series of problems with iOS 9.3, forcing it to roll out several updates.
"Mine is bricked," said one iPad Pad 9.7 user on the MacRumors forum. "Says it needs to be plugged into iTunes, won't restore or update, just a big loop. Fantastic."
Another poster on MacRumors said: "Yep, same here (9.7" iPad Pro). Can't restore from iTunes either. Completely fails. The 12.9" iPad Pro is fine, as is the iPhone 6S Plus. Another quality firmware release, clearly."
One Twitter user bemoaned: "iOS 9.2.3 has left my iPad Pro 9.7 in limbo. Can't install, can't restore."
The "Error 56" message points to a hardware issue, according to Apple's iOS error page. Apple's advice is to make sure you have the latest version of iTunes, check for issues with third-party security software, make sure your USB cable and other hardware are reliable and then try a couple of times to restore your device. If all that fails, then it's time to contact Apple support.