MacBook Pro screen goes full brightness

Same issue here. Just adding more experiences so Apple know it's not isolated. Macbook is on, display set to my normal brightness (barely above half) with "Automatically Adjust Brightness" turned off. Plug in my Dell 24" external monitor via USB C, open the Macbook, brightness is full blast.

Hey! I tried turn "automatically adjust brightness" off, didn't help. BTW for the last 4 days I did a lot, currently this bug is not appearing, fortunately for me ))

1st and main thing that I did is: set display profile to the same as built-in is using in my case is "Colour LCD" in system preferences - > Displays -> Colour tab

2nd - In Energy saver -> Power Adapter I have enabled only "Put hard disks to sleep"

Today I will enable all the rest in Energy saver back to default. I will update

Having the same issue of my monitors going to full brightness after I've pull back the brightness slider. Usually happens after the screens go to sleep then wakes. (All the saved palettes in my Adobe CC apps get all jumbled to and must be reset, not sure if this is related).

I have the 16" MBP with 2 LG 5k Ultrafines. Kind of annoying.

It works fine? No it doesn’t, it might be ok for some people who don’t need to calibrate their screens perfectly but for people who are using their mac as a tool ans not a toy it can’t be ok. 5000€ for a computer and this one can’t keep a screen lighting adjustement stable is unaceptable.

I have the same problem as everyone as well. 16" MacBook Pro, 5 k LG Ultrafine. Both screens to to full brightness when I plug in the monitor to the MacBook Pro, or when putting the MacBook Pro to lock screen.

Definitely a bug that needs to be fixed asap.

What do you mean by doesn't work? The button doesn't open when you click on it or when you select Copy Report it doesn't copy it?

If it's the latter try copying the report, open TextEdit and see if you can paste there.

I also have my screen calibrated to a specific brightness and also an external monitor. Every time I come back to my computer it's up to 100%. I was accusing my children of messing with it until I realized it was happening when I hadn't let them use the computer. Now I'm realizing it happens every **** time my computer goes to sleep. I use my computer for photo editing so I absolutely never have my monitors turned up to max brightness. Aside from being unacceptable from a utilitarian standpoint it's also blinding.

Running Catalina on a late 2014 Mac mini and my main monitor is an LG UltraFine Display, side monitor is ASUS PB278 Display, both 27".

A quick workaround until a fix is found is to not let your Mac sleep but just use the screensaver. There are some long time users here that have stopped using the sleep mode for quite some time for a variety of reasons.

Same as others: When an external monitor is connected, every time the Mac wakes from sleep the internal monitor resets to maximum brightness. Experienced on both iMac at home and MacBook Pro at work. I have submitted Apple Feedback, but given that the list of OS versions is usually one or two behind I doubt they ever read it.

Exact same issue.

Sporadically, my LG Ultrafine external display defaults back to max brightness upon unlock. This was never an issue until I updated to Catalina last October. I'm currently on 10.15.2, and the issue persists.

Current "solution" is to have my display settings open all the time so I can quickly dim the display.

I'd been consistently having this issue of my two external LG 5K displays changing to max bright every time my MBP15 woke since ~October 2019 when I updated to Catalina.

I'm happy to report that the last ~3 days the issue has NOT happened. I followed my standard unchanged routine that previously was causing the issue 100% of the time but the last few days the issue has occurred 0% of the time. When I wake up the external displays have been at the same brightness I set them at the previous day prior to disconnecting and using my laptop away from my desk, and then reconnecting and waking.

I'm hopeful this means that Apple has fixed the bug! Time will tell.

I'm currently running Catalina 10.15.2. I've got this computer setup to automatically install updates and I'm not aware of a way in Catalina to view the history of updates so I can't tell if there was an OS patch that occurred around the time the display brightness issue resolved.

Hopefully other people are also seeing improved behavior?

I just setup a new MacBookPro 16 (Catalina, of course). I run multiple displays for my photography business. I need this fixed ASAP as I run profiled displays (i1 Display Pro) for accurate colour and grey scale.

I have 12 days to consider a return. I hope this gets fixed by Apple soon, but there is no certainty as to if and when, so my multi thousand dollar purchase may as well go back until it IS fixed. I'm going to check here regularly as well as call support (today was my first day with the new Mac running on two displays (internal and LG 5G Ultrafine)

As an FYI I packed it up and will be returning it to Apple tomorrow while I'm still in my 14 day new product return period. I suspect Apple will fix or repair this in time but I'm not going to wait around and hope. It's too annoying, and my old MacBook Pro doesn't do this. I did spend 2 hours or so with Apple level 2 tech support yesterday - they can't fix it and suggested a return/replacement. So refund tomorrow and wait to see what the resolution is. Pls post here if and when there is a true fix. Thanks!

Apple Support had me go through SMS and NVRAM resets but the problem persisted. This was no solution for me.

I could have lived with it only happening on restarts - then I could expect if and when it would occur and I don't restart more than once a day unless installing software. My issue was it reset Brightness not only on restart but on Wake from Sleep which means potentially multiple times per day.

I will emphasize that my 16" MacBook Pro is going back only because I am still in the 14 day no questions asked return period.

Catalina also affected my older 15" MacBook Pro with Brightness to 100% bug but only if I plug or unplug the external LG and restart. It's solid through the day. And it never did even this before Catalina.