macOS Display Problems
After every reboot, the LG 5K display goes to maximum brightness.
Is this the worst bug in the world? Not even close. It’s a paper-cut bug. No data loss, no crash, not something sort of thing where something doesn’t even work — just an annoyance. But no one wants to use a tool that gives you half dozen paper cuts every day. And MacOS 10.15 is chockablock with paper-cut bugs.
I don’t have an LG 5K, but I’ve been having problems with multiple external displays ever since getting a USB-C Mac. Sometimes the Mac sees the external display, and puts windows on it, but the display itself shows only black (yet isn’t asleep). Rebooting the Mac doesn’t help. Shutting down the Mac and unplugging/replugging the display doesn’t help. Rebooting the Mac without the display and then shutting down and plugging it in doesn’t help. The only thing that seems to help is swapping the display to another USB-C port—thankfully, I have more than one. Then, a while later, the problem repeats and I have to switch back to the first USB-C port.
My 16” MBP is waking itself up hundreds of times overnight, probably with the display on. Catalina is draining about 1/4 of the battery because of it.
The strangest bug with Apple’s USB-C stack is power saving will happily put the display to sleep, which disables USB hub power, causing force ejection of any external drives you have, potentially corrupting them.
Any chance this is why external monitors cause a watchdog panic and reboot when my iMac sleeps under Catalina? I’ve heard that external drives can cause it too.
I didn’t even mention it in my post, but I’d say about 1 in 10 times I open my 16-inch MBP, the built-in display contrast is waaaaay off. Way too much contrast. I can fix it either by moving brightness all the way down then back up again, or by closing and reopening the lid.
The LG 5K is C U R S E D
We bought 10 for the company and it was the single dumbest hardware purchase decision I ever made.
An external display can be a good way of adding more USB-C ports to a Mac, but a strange bug can cause a lot of trouble with this otherwise excellent solution.
As I wrote back in November last year, letting an external display sleep can precipitate a kernel panic or other problem when the display goes to sleep, or the Mac tries to wake it up.
But it is much worse than I realized: when I reboot after some time, Crapalina 10.15.3:
- Reverses the Arrangement of the displays left vs right.
- Moves the menu bar to the wrong display.
- Makes 2560 X 1600 resolution unavailable on my NEC PA302W—I have to reboot a 2nd time, which somehow retains the menu bar and Arrangement and I can then use 2560 X 1600.
Previously:
Update (2020-02-18): Collin Allen:
Catalina bug: Coming out of sleep or screensaver, my whole display (except for the mouse cursor!) is washed out. Closing and re-opening the lid fixes it. A reboot makes it go away for a few days. 🤷♂️
Update (2020-02-26): John Gruber:
For me (16” MBP), more commonly, the problem is over-saturation, not under-saturation. But I’ve seen both, and in both cases you can “fix” it by either closing/reopening lid, or by sliding the brightness slider all the way down and then back up.
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Here we are 1/3 of the way through Tim Apple’s Catalina OS lifecycle (lackadaisical non-decimal version numbers not withstanding), and I’m still wondering what value there is in—
—upgrading to Catalina?
—spending 1000s of dollars for the “privilege” of data loss and Windozesque “death of a thousand cuts” bugs?
—now we can add “hardware beta tester” to ownership as it seems Apple doesn’t do hardware compat testing either.
Scott Forstall was ousted for FAR LESS.
Personally? I’m happy with 2015 kit and Mojave. Time offset Apple is best Apple.
How ironic, my 2019 Hackintosh running a 4 year old 5K Dell UP2715K runs perfectly. No hardware issues whatsoever.
I realise this display is a) no longer available and b) requires dual DisplayPort cables, but as a desktop display it's pretty much perfect.
Have a 4k HP 24" display. (3840x2160) running over USB-C -> displayport from a MBP 15".
Catalina decided to run it at 30Hz instead of the optimal 60Hz, and unplugging/replugging, changing scaling modes would not fix it.
The solution:
Open system preferences. Set Resolution back to "Default for display". Change rotation away from "standard", and then back to standard.
3 of my team members have the same display and we all ran into the same issue. wtf.
@ryan I use EasyRes to quickly adjust display resolution/refresh rate:
https://apps.apple.com/gb/app/easyres/id688211836?mt=12
For some reason, after booting, macOS often resets the resolution of my LG 4K display. EasyRes is the solution.
I have a LG 5K monitor at home and am seeing the issue Michael has - half the time when I wake my 16 inch MBP the monitor doesn't wake up. Unplugging USB-C cable some times fixes it but not always. So far a reboot has always fixed it. At work, I have an LG 4K monitor and I don't seem to have the same problem with it (although my work machine is a 2017 15 inch MBP).
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It still confounds me how the industry has yet to produce a reliable 5K monitor, much less one with a matte coating. Will such a seemingly-sensible product ever exist?
Well at least I'm not the only one with the "washed out" display after wake issue. I reported it as FB7567527, but of course it's probably not even been screened by a human, like most of my other reports.
