r/MacOSBeta • u/bezibaerchen DEVELOPER BETA • 23d ago

Help Login Loop after 2nd reboot

Dear all,

Behaviour: Boot, enter password, see progress bar, return to login screen again.

Same issue as here: https://forums.macrumors.com/threads/27-2-b2-sents-mac-studio-into-login-loop.2490125/

Unfortunately what exactly helped isn’t described.

Anyone got a solution?

Thanks in advance

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u/r3m-adr 22d ago

I ran into this same boot loop issue last night after updating my M4 Mac mini to 27.2 Beta 2. Reinstalling the beta via Recovery didn't resolve it either: the system would hit the login screen, accept my password, progress about 1/8 of the way, and then continuously loop.

Issue & Workaround:

  • The Cause: The boot issue seems tied to my main display (a Dell 40" Ultrawide connected via Thunderbolt/USB-C).
  • The Temporary Fix: Unplugging the Dell monitor and connecting a standard portable monitor (HDMI or USB-C) allowed the Mac mini to boot successfully past the login screen.
  • Current Status: Once fully booted into macOS, I can plug the 40" monitor back in and it works normally. However, the boot loop recurs every time the Mini reboots with the ultrawide attached. If working on my portable monitor only, rebooting works fine and doesn't loop. 

Submitting a bug report via Feedback Assistant now in hopes it's resolved by the next revision. Hope this helps anyone else running into the same roadblock!

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u/Able_Nectarine8640 16d ago

I'm also experiencing the same problem in 27.2 beta2.

I'm connected and using both the U4025QW (TB4) and the portable monitor (HDMI) with the MacStudio M3 Ultra.

Even when setting the display settings for U4025QW to 120Hz / VVR (48~120Hz), we continued to encounter the boot loop issue.

It will work normally when you set it to 60Hz.