[GH-ISSUE #846] MacBook display dims unexpectedly, after a while #536

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opened 2026-05-05 06:12:07 -06:00 by gitea-mirror · 3 comments

gitea-mirror commented

2026-05-05 06:12:07 -06:00

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Originally created by @ymshulman on GitHub (Dec 17, 2021).
Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/846

Before opening the issue, have you...?

Searched for existing issues
Looked through the wiki
Updated MonitorControl to the latest version (if applicable)

Describe the bug

MacBook display dims unexpectedly. Can't figure out when it happens; but it happens consistently during any working session of over 30 minutes.

Steps to reproduce

Plug in external monitor. Work on external monitor.
(Seems to reproduce more quickly if I'm working on the external monitor than if I'm going back and forth between the two; but it does happen both ways.)

Expected behavior

Display should only dim if I tell it to. I have not touched the keyboard buttons or any software sliders to make this happen.

Anything else?

n/a

Environment Information (please complete the following information)

- macOS version: 12.0.1 
- Mac model: Macbook Pro (15-inch, 2018) 
- MonitorControl version: v4.0.2 
- Monitor(s): LG ultrawide 29" (2560x1080) 
- Apple Silicon/M1 (yes or no): no

Originally created by @ymshulman on GitHub (Dec 17, 2021). Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/846 ### Before opening the issue, have you...? - [X] Searched for existing issues - [X] Looked through [the wiki](https://github.com/MonitorControl/MonitorControl/wiki) - [X] Updated MonitorControl to the latest version (if applicable) ### Describe the bug MacBook display dims unexpectedly. Can't figure out when it happens; but it happens consistently during any working session of over 30 minutes. ### Steps to reproduce 1. Plug in external monitor. Work on external monitor. (Seems to reproduce more quickly if I'm working on the external monitor than if I'm going back and forth between the two; but it does happen both ways.) ### Expected behavior Display should only dim if I tell it to. I have not touched the keyboard buttons or any software sliders to make this happen. ### Anything else? n/a ### Environment Information (please complete the following information) ```markdown - macOS version: 12.0.1 - Mac model: Macbook Pro (15-inch, 2018) - MonitorControl version: v4.0.2 - Monitor(s): LG ultrawide 29" (2560x1080) - Apple Silicon/M1 (yes or no): no ```

gitea-mirror

2026-05-05 06:12:07 -06:00

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gitea-mirror commented

2026-05-05 06:12:12 -06:00

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@waydabber commented on GitHub (Dec 21, 2021):

To be honest I have no idea what's causing this. :) whenever it happens, it would be great to see al .info level log entries for MonitorControl (via the Console). MC should not change the brightness by itself. Are you sure this does not happen when MonitorControl is not running (maybe a faulty amibent light sensor?)

(check this https://github.com/MonitorControl/MonitorControl/discussions/851 out for help on how to see the logs)

@waydabber commented on GitHub (Dec 21, 2021): To be honest I have no idea what's causing this. :) whenever it happens, it would be great to see al `.info` level log entries for MonitorControl (via the Console). MC should not change the brightness by itself. Are you sure this does not happen when MonitorControl is not running (maybe a faulty amibent light sensor?) (check this https://github.com/MonitorControl/MonitorControl/discussions/851 out for help on how to see the logs)

gitea-mirror commented

2026-05-05 06:12:13 -06:00

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@ymshulman commented on GitHub (Dec 21, 2021):

I’ll try to grab those logs. But yes - I’m sure this doesn’t happen when
MonitorControl is not running, and has never happened before I installed
it.

On Tue, Dec 21, 2021 at 4:36 AM Istvan Toth @.***>
wrote:

To be honest I have no idea what's causing this. :) whenever it happens,
it would be great to see al .info level log entries for MonitorControl
(via the Console). MC should not change the brightness by itself. Are you
sure this does not happen when MonitorControl is not running (maybe a
faulty amibent light sensor?)

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@ymshulman commented on GitHub (Dec 21, 2021): I’ll try to grab those logs. But yes - I’m sure this doesn’t happen when MonitorControl is not running, and has never happened before I installed it. On Tue, Dec 21, 2021 at 4:36 AM Istvan Toth ***@***.***> wrote: > To be honest I have no idea what's causing this. :) whenever it happens, > it would be great to see al .info level log entries for MonitorControl > (via the Console). MC should not change the brightness by itself. Are you > sure this does not happen when MonitorControl is not running (maybe a > faulty amibent light sensor?) > > — > Reply to this email directly, view it on GitHub > <https://github.com/MonitorControl/MonitorControl/issues/846#issuecomment-998620339>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/ACPJ2DAXDZ7PEN2MVKMJUWLUSBDB5ANCNFSM5KJVL72A> > . > Triage notifications on the go with GitHub Mobile for iOS > <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> > or Android > <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. > > You are receiving this because you authored the thread.Message ID: > ***@***.***> >

gitea-mirror commented

2026-05-05 06:12:14 -06:00

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@erikblomqvist commented on GitHub (Feb 2, 2022):

@ymshulman I actually stumbled upon this problem as well, but I think I know what caused it and how to fix it.

If you go to System Preferences > Displays > Display Settings… and select the Built-in Retina Display in the left-hand sidebar, you just uncheck Automatically adjust brightness. Haven't had the problem since.

@erikblomqvist commented on GitHub (Feb 2, 2022): @ymshulman I actually stumbled upon this problem as well, but I think I know what caused it and how to fix it. If you go to **System Preferences > Displays > Display Settings…** and select the Built-in Retina Display in the left-hand sidebar, you just uncheck **Automatically adjust brightness**. Haven't had the problem since.