Random behavior of my Mac's screen and difficulty turning it back on

Just curious of the exact model of your Mac and version of macOS. You can get this information by clicking the Apple menu and selecting "About This Mac".

I have been seeing issues where the screen brightness keeps dimming on the M-series Macs. I'll adjust the brightness to full and a little while later with the laptop not even going to sleep or locking the screen I will find the brightness has dimmed......sometimes to half. I have disabled the "Dim display" option when on battery. I haven't looked any further since these Macs are being managed by my organization so there is a slim chance they have configured some setting that I'm not seeing or is not shown in the GUI. I haven't been working with any Intel Macs to compare if it is definitely an M-series Mac issue or a macOS issue.

You can try clearing the NVRAM to see if that makes any difference. Within the Terminal app, enter the following command (it is safe for M-series Macs):

sudo  nvram  -c

You will be prompted for your admin password. Nothing will appear on the screen as you type the password, so press the "Return" key to submit the password. You may see "permission denied" messages for certain keys such as Computer Name, but if you don't see any error message regarding the failure of the command to execute, then reboot the computer in order for the system to pull the default values from the NVRAM on boot.

You can also try a DFU firmware Revive which resets the security enclave chip & system firmware. I doubt this will help here, but it is about the only other thing I can think to try other than reinstalling macOS over top of itself (even better would be to test a clean install of macOS without restoring from a backup...for testing purposes).

If this is something you can reproduce on demand, then you have have Apple or an Apple Authorized Service Provider examine the laptop. I know on my organization's Macs, this issue seems to be fairly easy to reproduce.

I think the problem is related to the light sensor. When the laptop senses less light in the room, macOS automatically dims the screen. I just haven't done any thorough troubleshooting to confirm this is the trigger. Theoretically once the laptop is in bright light, then the screen brightness should automatically increase. FYI, I have only seen this issue on my organization's managed laptops (MBAir M1).....I have not seen the issue on either of my two unmanaged M-series laptops (both MBPros) so I it may be a configuration issue or just an issue with the MBAir M1.

You can provide Apple with product feedback here:

Product Feedback - Apple

If you want Apple to take an active role in this, then you will need to open an official support case with Apple Support & ask to have the issue escalated if the first tier support agents are unable to resolve the issue. Just providing feedback won't get Apple to actively look into the issue unless enough people have also reported the issue.

hsetti wrote:

Hello,

I have a MacBook Pro 14" with the M3 chip, running macOS 15.1 (24B83) (the latest version). As far as I know, with the M3 chip, there’s no need to reset NVRAM since simply shutting down the Mac will reset it. Is that correct?

You are confusing NVRAM reset with an SMC Reset although there is no traditional PRAM Reset (NVRAM reset) on the M-series Macs using any special startup key commands. The special startup key commands are only for the Intel Macs. However, the M-series Macs do still have NVRAM which can be cleared using the command line as I mentioned in my previous post. I have seen these M-series Macs get stuck with bad NVRAM settings that have prevented normal booting.

Sometimes reinstalling macOS over top of itself can fix some issues, but I doubt that is likely to help here. Same with the DFU firmware Revive, but they are options you can try if the NVRAM reset using the command line does not help. I guess even trying to delete the .plist preference/setting file where the "dim display" setting is stored may also be a possibility as well (I don't know which file that would be)

I was able to reproduce the issue: when I’m in a dark room with the “Adjust brightness automatically” option enabled, the screen goes dark after minutes, and pressing any key or mouse (except the brightness button or turn up the room's light) doesn’t wake up the screen. However, when this option is disabled, the issue doesn’t occur.

I have just noticed that my organization's MBAir (M1, 2020) laptops running macOS 14.x Sonoma seem to drastically dim their screens even after I have set the brightness to 100% (the setting to dim the display on battery is turned off/unchecked). I have found that if I cover the camera & let the screen dim, then adjust the brightness to 100% again while the camera is still covered seems to help prevent the display from dimming later on (at least it occurs less often).

What would you recommend I should do?

If these suggestions don't help, then it will probably require an experienced tech to examine the laptop to see the issue first hand.

You could try creating a new macOS user account. Log out of your current macOS user account & log into the new user account. Does the problem still occur? If not, then you know the issue is limited to a configuration issue with your main user account.

I guess you could also try a clean install of macOS & testing the behavior with the clean install to see how that works without any third party software installed & without restoring from a backup. A clean install is when you erase the disk (or rather delete the Volume Group on an M-series Mac) & reinstall macOS....or by performing a DFU firmware Restore which resets the security enclave chip & system firmware as well as pushing a clean copy of macOS onto the internal SSD. A less thorough option if you have more than 80GB of Free storage space (ignore the "Available" storage value since it is very misleading) would be to create a new APFS volume & install macOS onto that new APFS volume so you have two macOS installations side by side....if this works, then you can feel fairly confident that the hardware is Ok & you have a software or configuration issue with the original OS installation.