iPhone unlock Apple Watch stopped working after Siri AI installation

I've experienced an issue with iOS 27 and watchOS 27 when I've installed Siri AI (as distinct from Siri Classic). I had it set up so that my iPhone (15 Pro Max) unlocked my Apple watch (Series 10), but after installing Siri AI that stopped working. I tried toggling the "unlock with phone" switch in the Watch app, then resetting the watch, but in the end I had to completely reset and unpair the watch, then go back to a backup of the watch taken before the update to WatchOS 27 and before Siri AI was installed, and pair the watch from scratch again. That sorted it.

This is a shame, as I'd really like to use Siri AI and unlock watch with phone. Any ideas?

Many thanks, Mark

Posted on Sep 20, 2026 10:39 AM

1 reply

Mark Farthing Author

Level 1 (7 points)

Sep 20, 2026 11:16 AM in response to Mark Farthing

Update - it now does work. It took its time though! First of all, I pulled down the notifications, then pushed them back up - and hey presto it unlocked the watch. Then after a few minutes, it did it all on its own. It's just that it used to be instant, and with Siri AI it took a while to start working.