Monday's watchOS 3.1.1 update has rendered some Apple Watches useless, forcing their owners to turn to Apple for a replacement, according to a series of user complaints.

Affected Watches are ending up on a screen with a red exclamation mark, and a link to www.apple.com/help/watch. In practice, though, even Apple stores can't deal with the problem directly, which purportedly involves connecting to a Watch's diagnostic port to restore the device.

Instead Apple stores are apparently sending units off, making it easier in some cases to use the company's support site and apply for a replacement by mail.

While the problem primarily appears to be affecting Series 2 Watches, some earlier models may also be impacted. Since even many Series 2 owners haven't experienced any trouble, though, it's not clear what the root cause might be.