Led Cinema Display brightness control not working after upgraded to macOS Monterey

What sort of an adapter did you use to connect your LED Cinema Display to your Mac Studio? My Mac Studio is a few weeks away from delivery, and I'd like to be able to use my LED Cinema Display/24" with it.

Thanks for the suggestion but no joy, I'm afraid.

Do I need to restart or change any other setting?

I'm also wondering if I should uninstall the other two controls recently added: Lunar and Brightness Slider, as they also have no effect?

in my case, I can power off the Cinema Display using the button in the Lunar menu bar drop down menu, so I know that Lunar can 'see' the Cinema Display but Lunar doesn't change, let alone increase brightness at all.

I must admit to being quite confused by the many Lunar settings. Being under the impression that it should work straight away, I have not changed any of them but perhaps someone who know more about could suggest otherwise?

Thank you for your suggestions. In case of a conflict between Lunar and MonitorControl, I quit Lunar and made the adjustments to MonitorControl preferences that you describe but all to no avail. My Cinema Display remain resolutely stuck at 50% brightness and nothing will increase it.

It is both frustrating and tantalising, in that the onscreen Brightness display (when using the keyboard control) continues to rise above the 50% mark even without having any effect on the actual screen brightness. Sometimes a little lock symbol appears alongside but I have no idea how to unlock it.

Thanks again. I think you may be right. I don't have AppCleaner but I do have Cleaner One Pro, which does the same thing. I'll run it and then reinstall MonitorControl, as you suggest.

I don't know what F-Secure is and don't anything installed with a similar name, so hopefully, will not have any issue in that regard. Will report back later.

Do you have an old wired mouse somewhere? They tend to always work. You can connect the USB-A plug of the display to your Macbook, and the mouse directly to the display.

Also you can try to set your keyboard to move the cursor in Accessibility preferences. Or quickly hit the Option(cmd) key five times, that should activate Mouse Keys. Then you can use the keys 7 8 9 U O J K L to move the cursor. On an extended keyboard you use the number keypad on the right.

Or you can bring your display to a friend with an Intel Mac and set it to 100% there ;)

Yes, thanks. I did connect a mouse via USB - USB C converter but the MacBook Pro struggled with that too. The 5x Option key trick is new to me though. I will keep it in mind when I next attempt to get to 100% brightness.

Only slight snag holding me back from doing it right away is that each time I disconnect and reconnect the Cinema HD display to the Mac Studio, the Display Preferences go a little berserk, the CinemaHD becomes the primary monitor instead of the extension, their relative positions get reversed and if the iPad is connected too, it has a minor nervous breakdown! Alright, it's not the end of the world but it is quite annoying and time consuming to get everything back in order.

Again, ran through the process of setting the brightness on the Cinema HD via the MacBookPro. No connection issues this time but there was no extra brightness to be got, nor any way of adjusting it. Tried again via an iMac running BigSur but again, no control or adjustment in brightness.

Reconnected the Cinema HD to the MacStudio. It flickered to life briefly then went black and though still visible in Displays Preferences and MonitorControl, would not respond to either. Restarted and rebooted but still black.

Not sure what to try next?

Of course, it could be that the Cinema HD has reached the end of its natural life. Can it be repaired? I have two of these former beauties, now both defunct alas. It would be lovely to get at least one of them back to useful life.

Thanks, nguyendk, that's actually very helpful. I did try connecting the Cinema HD to my MacBook Pro but hadn't installed Monitor Control on the laptop and only managed to get the monitor up to about 85% when reconnected to the Mac Studio.

Incidentally, the flickering and black screen I mentioned in an earlier post was caused by overheating, I've since discovered. A problem that was exacerbated by the positioning of the monitor in direct sunlight. It has never been a problem before but the extreme high temperatures we've been experiencing this year must have put it over the edge. Switching off the power and allowing the monitor to cool off seems to do the trick.

Yes, same here with 24" Led Cinema display, Mac mini M1. Even brightness slider displayed by Siri does nothing!

worked fine before, for many years.

Hoping for a bug fix in next update.

I have a M1 MBA and after updated to Monterey the brightness adjustment is not working for Apple Cinema Display 27". I downgraded to Big Sur to use this. So sad. Apple please help

same problem with a M1 16" with a apple cinema 27"..

but nothing 3rd party app fix this problem..

i

thanks for your post.

im sure you issue is not fixed with a 3th party app.

MonitorControl reduces the colours, whereas lunar.fyi actually changes the brightness of the panel