Owners of the Apple Watch Series 12 and Ultra 4 have reported a bug that causes the devices to restart unexpectedly. According to ZDNET, the issue can occur while the user is simply adjusting a setting, with the watch shutting down and rebooting without warning. One user on Apple's Support Community found a panic-full file in the diagnostic logs, pointing to a timeout in the Neural Engine, the hardware block that handles AI and security tasks.
Apple has released watchOS 27.0.1 to fix the problem. The update arrived late Wednesday and is available through the Watch app on an iPhone or directly via the watch's Settings menu. ZDNET notes that Apple's support page describes the update as containing multiple bug fixes, though the restart issue appears limited to the Series 12 and Ultra 4.
For those affected, the fix is straightforward: install watchOS 27.0.1. Users who want to confirm the cause can check their diagnostics logs under General in the Watch app and look for a panic-full entry. ZDNET's own reporter had experienced the restart twice before applying the update, and while it was too soon to confirm the fix, Apple typically resolves such issues promptly.