Some users report a macOS Catalina bug that sees displays reset to max brightness after sleeping

LG Ultrafine monitors
LG Ultrafine monitors (Image credit: iMore)

What you need to know

  • Multiple people are being blinded by their Macs.
  • The display brightness is being set to 100% after sleeping.
  • It doesn't matter what the display was set to when the Mac slept.

Some users of macOS Catalina have noted that their displays are doing strange things when their Mac wakes from sleep. No matter what brightness they were set to before sleeping, they're waking at 100%. And that's very bright indeed depending on the display you're using.

This was initially reported by Mac Performance Guide as impacting those using LG's external 5K display, but we've also seen additional reports that suggest it could be happening with other displays as well. Specifically, the super fancy Pro Display XDR.

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Others say they've been experiencing similar display-related issues with brand new 16-inch MacBook Pro notebooks as well. This from John Gruber who also wrote this up for Daring Fireball.

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And then there's iMac Pro, too.

We had this same exact issue with an iMac Pro when they were first released.Bought 2 machines and one of them was useless to us with this issue.After a long time with Apple support, they said it was a known issue but there was no solution at the time. Eventually I was able to convince them to take the machine back if I ordered another and it was problem free. Ordered another, it was fine and they took the problem one back.Sorry to see the issue is still around.

It's certainly not beyond macOS Catalina to carry a bug or ten, but we can imagine this one being particularly irritating if you're someone who needs their Mac to be "just right" for things like photo and video editing. Gruber pointed to one user who just couldn't live with having to re-calibrate their display repeatedly each and every day. So they just returned their Mac.

A DF reader — also a professional photographer — wrote to me about this bug last week. He (the DF reader) was using a $6,000 new 16-inch MacBook Pro. I say was, past tense, because after a few days he returned it because this brightness issue was no small thing for him, because he sets his display brightness precisely using a display calibrator. Doing this several times per day every day quickly drove him mad.


Oliver Haslam

Oliver Haslam has written about Apple and the wider technology business for more than a decade with bylines on How-To Geek, PC Mag, iDownloadBlog, and many more. He has also been published in print for Macworld, including cover stories. At iMore, Oliver is involved in daily news coverage and, not being short of opinions, has been known to 'explain' those thoughts in more detail, too.

Having grown up using PCs and spending far too much money on graphics card and flashy RAM, Oliver switched to the Mac with a G5 iMac and hasn't looked back. Since then he's seen the growth of the smartphone world, backed by iPhone, and new product categories come and go. Current expertise includes iOS, macOS, streaming services, and pretty much anything that has a battery or plugs into a wall. Oliver also covers mobile gaming for iMore, with Apple Arcade a particular focus. He's been gaming since the Atari 2600 days and still struggles to comprehend the fact he can play console quality titles on his pocket computer.