Second display "Led Cinema Display" turns darker after login on my iMac.

My second display goes darker after login. When I turn on the iMac both monitors are equally bright and then after login in the second display goes darker and I can't change it in settings or anything. What to do?

iMac 27″, macOS 12.7

Posted on Feb 8, 2025 9:11 AM

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2 replies

samtenor

Level 4

2,074 points

Feb 8, 2025 4:56 PM in response to JaiL

Change your Mac display’s brightness - Apple Support

I assumed your set up is "extended display mode" with these 2 displays.

I think The LED Cinema Display does not have ambient light sensor, so you can just go the the "Manually Adjust Brightness" portion.

Best

JaiL Author

Level 1

7 points

Feb 9, 2025 3:01 AM in response to samtenor

Not very useful cause both displays (iMac & Led Cinema) is equally bright before login. Doesn’t matter if I use guest login or my own.

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Second display "Led Cinema Display" turns darker after login on my iMac.

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