After upgrading to Catalina, MacBook Pro ups its screen brightness to max every time I connect an external monitor (any external monitor). Is there a solution? I am using manual brightness.
MacBook Pro with Touch Bar
I usually do not restart MacOS unless I have an update or something. I connect and disconnect external monitors when needed. Even if I do not physically disconnect a monitor, but turn it off with a button and then turn back on again, the built-in monitor goes into full brightness. This was not the case with OS versions prior to Catalina and is clearly a bug. This is not critical bug and I can live with this. I am a Software Developer and I do this for a living. If Apple pays me to help localizing this bug fix this, I can spend time on this task. But otherwise - no worries.
What works for you?
Hi, just to let you know, the fix only lasted a few days for me. Just as you said it would.. :-)
Got a new Mac update last night and SO FAR I haven't noticed the issue. Here's to hoping they sorted it out!
I should say I'm on Catalina 10.15.3
Can you be more specific on the update?
10.15.3?
please let us know
Yes, 10.15.3. I posted that right after my reply saying it was working.
Yes, thank you! I’m traveling and apologize for not remembering your previous post.
still behaving well?
Actually no :-( Just plugged the external monitor in with the lid closed this morning, opened it up, and full brightness.
No change with my screen going 100% brighteness either. 10.15.3 is not a fix.
I have the same issue, happens in bootcamp aswell now and again.
Good to see that its Apple's fault and that they will have to fix it!
Same here, when I restart my 15" 2017 MBP. Full brightness on my laptop, my external EIZO is cool.
Yup. My external NEC is fine. I'm guessing it's an interaction with Thunderbolt 3 /USB video controllers .
This problem was first reported in NOVEMBER 2019! I'm writing this in early February.....
Can't believe this isn't fixed yet. Catalina is just buggy all around.
It could be TB3 issue. My external monitor (Dell 2415) connects to my iMac through a TB3 to HDMI converter.
It’s at least related to external monitors.
My external EIZO it’s fine and connected through DisplayPort. The native 2017 MacBook Pro goes to max brightness on every start up.
MacBook Pro screen goes full brightness
