Archive. This is an archive of the Apple Support Community. Discussions are being restored and soon you will be able to read and post here again.
jfaughnan
User level: Level 3 (920 points)

MacBook Pro freezes during Fast User Switching with portrait external monitor

Complete system lockup on Fast User Switching with portrait monitor


I ran into a problem that was reported as a bug in 27.2. It's not fixed in 27.2.1. Sharing here to help others. It did not occur in Tahoe.


When switching users with Fast User Switching the Mac froze at login for the new user. No change over 12h. It was easy to replicate. Went away when I disconnected external monitor.


ai suggested it was related to having my MacBook Pro external monitor rotated 90 to portrait mode. It's an old monitor, very standard resolution.


Switching external monitor to landscape mode (standard rotation) fixed the problem.


I do miss my portrait monitor orientation.

Posted on Nov 10, 2026 7:52 AM

1 reply

neuroanatomist
User level: Level 9 (72,871 points)

Nov 10, 2026 7:58 AM in response to jfaughnan

Note that this is Apple Support Communities, not Apple Support. “We” are users like you and have no power to implement any suggestions. Apple employees are generally precluded from even reading these forums, with the exception of moderators who only monitor for compliance with the T&C.

 

Bugs can be reported to Apple here:

Feedback - macOS - Apple


FYI, the 27.2.1 update was a patch for security issues with certain native applications, AirDrop, etc., and was not intended to address any UI bugs.

Originally posted at discussions.apple.com/thread/256392018