MacBook Pro screen goes full brightness

Hi Satherton

Go to the Apple Menu (upper left top of your screen) and choose About this Mac

It should be the first item

The result will tell you which version of Catalina you updated to.

I will guess it’s 10.15.3

please let us know

this is how we can see if user experiences in a “fix” relates to a particular update version.

thanks!

Hi Dickie7. You are very right. I've been using two LG 5K TB3 displays purchased from the Apple store a few years ago, along with a MBP 15 2016.

Since the beginning the interface between the displays and the MBP has been flaky and I share your "display connect PTSD". Sometimes it works perfectly for a few months. Sometimes it has crashed the entire computer forcing disconnect and reboot from the laptop. Sometimes it has issues with the displays not coming on correctly when they are plugged in. Sometimes weird patterns flash on the screen. Sometimes one display is completely dead until replugging. For a long time there were issues with displays coming on at a super slow refresh rate and looking flickery until replugged. Now for the last few months its been this brightness reset issue.

It's been really bad for years, ever since I purchased this setup for $$$$$. As you said, it's really nice when it works. But there have been so many problems for so long that I feel anxiety when I connect the displays, always wondering what will happen and preparing to execute some recovery sequence.

Sad. There really seems to be some issue with making this chipset or TB3 displays function reliably. Apple seems to have finally fixed some of the old problems such as the hard crashes and refresh rate since I've not seen those for maybe 6 months. But now we are enjoying the new brightness issue.

Remember this old Apple marketing slogan, "It just works."? Uh yeah.

/sigh

/sigh is right.

I'm like a broken record but....

Apple today seeded the first beta of an upcoming macOS Catalina 10.15.4 update to its public beta testing group.

If anyone here can or is willing to join the beta program and test fly 10.15.4 to see if there is a fix for the screen brightness issue I'd love to hear your results.

I'm down to one production Mac with TB3 so really don't want to load Beta releases.

Thanks everyone, Stephen

Same here with a MBP 15 2018 ... I'm pro photographer so it's a big problem for me ... How it's possible to see so much people with the same problem and to don't have answers from Apple ... I sad to up to Catalina, I hope no more problems

yoan2web - I'm a pro photographer too. It occurs with both my 2016 15" on Catalina and 2019 16" on Catalina (10.15.2 and 10.15.3). It effects my built in screen and my LG Ultrafine 5K. Note the LG is connected via Thunderbolt 3, so I'm suspecting a Thunderbolt related issue. My 30" NEC colour accurate display is not affected as it contains it's own LUT and display engine. Whew.

Best thing I can suggest is make as much noise as possible. I called Apple Support, went to tier 2, I write here, also write to the popular Mac blogs (Daring Fireball, DIgiLloyd, Macintouch. It's been repeated on iMore as well. Hopefully someone in Apple is getting the feedback and may prioritize this fix (there are so many others to do with Apple's 2019 software releases!

There's no solution yet.

A beta version of Catalina 10.15.4 is available if you want to try it.

Keep us up to date - Stephen

MacBook Pro 15’, Late 2017, macOS 10.15.3

Thunderbolt Display, connected via Apple's Adapter directly to MacBook Pro

I have never ever had this issue before I've Updated from macOS 10.14.6 to Catalina, 10.15.3.

Now, after every Restart, I see my MacBook Pro 15’ Screen at 100% Brightness!

I choose my Main/Admin User, Log In

MacBook Pro Screen stays the same, at 100% Brightness

Automatic Adjustment is Off.

Thunderbolt Display Brightness always stays the same. No problem with it!

I Adjust Brightness on MacBook Pro 15’ screen

I Restart, and my MacBook Pro 15’ Screen is back to 100% Brightness

I don't recall if this problem goes away if I disconnect my Thunderbolt Display or not!

With Thunderbolt Display connected to my MacBook Pro 15’, if I Hold Option during Restart, my MacBook Pro 15’ Screen Brightness is OK, just like I set it up!

Then I choose SuperDuper! Clone with macOS 10.14.6 on it to Start Up from, and my MacBook Pro 15’ Screen Brightness is OK, just like I set it up!

Obviously, it is Catalina 10.15.3 which had created this issue!

I don't think that this issue happens if I Disconnect my Thunderbolt Display during Startup!

I already mentioned this to AppleCare, and they told me that it's a Known Issue!

I am yet to address it with whatever Resets that they will suggest!

My Priority ONE for now is SLOW SYNC from Mac Music to Music on iPhone!

Now that there is no more iTunes with its own Sync, the same Library, that had been Imported into Music App, after Catalina 10.15.3 Update, is Syncing though Finder, and is 7-8 Times Slower! I.e a few Songs that used to take 2-3 minutes, now take 15-17 min Range!

The Syncing UI in Finder has no Progress Bar, thus the user does not know how long the Sync will be!

Other than that Catalina 10.15.3 seems to run faster, with Apps launching a lot quicker, and there are other improvements!

I hope that AppleCare will help me with this Slow Sync, and then with this Brightness Issue!

It'd be great if Apple did Monitor these Discussion Boards, and did acknowledge such issues! Or, at least did it via AppleCare...

Good Luck to everyone!!!

Catalina has many many issues which are known as "paper cuts" - ie: annoying and flawed but not damaging to hardware or your data. Think "Death by a thousand paper cuts" as the experience many people are having with this version currently of macOS.

The brightness issue for me only occurs when I have a Thunderbolt 3 monitor attached.

Apple is aware of the issue and may or may not prioritize a fix depending upon what other issues they are dealing with.

My Music app fails to load my iCloud play lists - and I have a few other issues - all of which I've tracked down to a third party disk driver. I have a support case in for this with the drive manufacturer. No resolution yet - and yes, a Catalina related problem.

I hope we can keep this discussion thread focussed on the 100% brightness issue - otherwise it will lose focus and be less helpful to users as time goes on. I've already pointed some other folks here with a link as they share the same issue.

Here's hoping the next macOS Catalina update 10.15.4 solves the problem :)

Stephen

This issue is driving me nuts. I have it too. MacBook Pro 16. Any display I attach, be it through a USB-C to Display port cable, a USB-C to HDMI dongle, the brightness goes to 100% every time I unlock my screen or plug the cable in. It happens with Samsung displays and LG displays. TrueTone and automatic brightness are disabled. For the love of god, Apple, respond and fix this thing.

Apple released an upgrade to Catalina today (March 24, 2020). V10.15.4

I have not yet had the chance to install it, however if anyone has and if it addresses the screen brightness issue let us know!

Stephen

I just got the 10.15.4 update but haven't had a chance to test it yet. One of the notes in the changelog says "Fixes an issue with screen brightness for the LG UltraFine 5K display after waking from sleep", so here's hoping!

Strangely enough, I switched from using an 2019 iMac with a singe external display to a 2015 Macbook with 2 external displays as part of my new work from home setup. the 100% brightness issue doesn’t occur on my Macbook Pro’s screen.

ie the Macbook Pro retina display never goes to 100% brightness by itself.

I am yet to install this macOS 10.15.4 Update on my

MacBook Pro 15’, Late 2017, macOS 10.15.3

I use Thunderbolt Display with it, via Thunderbolt 2 to 3 Apple Adapter.

My HDs are plugged in via OWC Thunderbolt 3, 13 Port Dock, which is plugged in via USB-C

I'd like to know:

Is there anyone here using a similar setup, or at least Thunderbolt Display?

Did this macOS 10.15.4 Update fix this Full/Max Brightness issue on the MacBook Pro?

If Yes, please specify exactly:

Which MacBook Pro model do you have?

Which External Display, and how it's connected to your Mac?

That way, if I am still having this Full/Max Brightness issue, I can refer AppleCare to this Discussion!

Thanks in advance for your Replies!

I updated to 10.15.4 a few days ago and so far I've had ZERO recurrences of the max screen brightness bug that appeared with Catalina. I've connected to my two LG 5K TB3 displays maybe 5-7 times since the update, all without the issue. Previously I saw the issue 90% of the time. I'm hopeful that the bug has been fixed in 10.15.4. So far so good!

I won’t be following thread this any longer as my 2019 iMac with the issue has sold , and the 2019 Macbook Pro 16” I replaced it with doesn’t have the issue. Same monitors and OS, but not issue.

From that I surmise the issue has something to do with my iMac. Note that there may be more that one cause for the same issue. So an OS patch may fix it for some, but not for others.

Good luck to those who are still experiencing this issue!

Yes, likewise this latest release seems to have done the trick for me as well (LG 5K/MacBookPro 16" 2019) and have been testing it for about a week now. Just a pity it has taken so long to resolve - I reported it back in December 2019 together with other issues.