LG UltraFine 5K - Issues/bugs

Weaselboy

Moderator
Staff member
Jan 23, 2005
29,786
9,443
California
Since updating to macOS 10.15.1 I have the bug that (sometimes) when I plug in my LG Ultrafine 5k into my MacBook Pro the brightness of both my MacBook Pro and the monitor get cranked up to 100%.

Anyone else also having this issue and knows a fix?
Yep... same here. No idea for a fix though.
 
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minimoo

macrumors newbie
Feb 3, 2013
3
0
I have recently got an older version 27MD5KA-B and 2017 MBP 15" top version and the computer is very slow, even just chrome web browser with 5-6 tabs and watching Youtube or Netflix. I guess video playback is kinda trigger of the problem.

I use it in clamshell mode and first I thought it's my laptop so did all "cleaning & optimisation" but didn't help then when I plugged out and use it as standalone laptop it runs perfectly no matter how many videos it's playing.

Anyone having this issue ?
 

goMac

macrumors 604
Apr 15, 2004
7,054
1,074
Are people still seeing the wavy line issue with new displays? I saw one person noticed that one exchange didn't have the issue. Wondering if that's a one time thing, or if people are getting displays now without the wavy lines.
 

CHA05 R31GN5

Suspended
Oct 31, 2019
165
257
United States
I have recently got an older version 27MD5KA-B and 2017 MBP 15" top version and the computer is very slow, even just chrome web browser with 5-6 tabs and watching Youtube or Netflix. I guess video playback is kinda trigger of the problem.

I use it in clamshell mode and first I thought it's my laptop so did all "cleaning & optimisation" but didn't help then when I plugged out and use it as standalone laptop it runs perfectly no matter how many videos it's playing.

Anyone having this issue ?
I've not used the display with the 555x/560x in some time when I had 10.14 installed. But, with my eGPU, I don't notice any lag that you're speaking about. Are you using any peripherals with the display's hub? Is the display connected directly to the MBP? Tried a different TB3 cable which supports 40GBps and 60-85W+ PD?
 

smileman

macrumors regular
Oct 23, 2011
125
19
Still having the sleep/wake issue after updating to Catalina. This happened on my 2016 15" MBP as well as my 2019 15" MBP.

What does get the LG monitor working is:

  1. logging out of my main MBP account
  2. logging into a separate admin account
  3. unplugging my Belkin cable and plugging it back in (LG monitor then comes on)
  4. logging out of the separate admin account and then back into my main account
Any suggestions on a more elegant permanent solution?
 
Last edited:

palter

macrumors member
Feb 17, 2006
59
30
Boston, MA
I just received my new 16" MacBook Pro (2.3 i9/32GB/1TB/5500M 4GB). I have an original UltraFine 5K purchased when I bought my 2016 MPB.

In clamshell mode (my normal setup), if I plug the UltraFine into the left side of my 16", everything works fine. However, if I plug it in on the right side, the display remains black.

If I run with the lid open and plug the UltraFine into the right side port, both screens continuously turn on and off. The actual display never appears on either, they just flash on and off.

I am using Apple's 0.8m Thunderbolt 3 cable.

Has anyone seen anything like this? Is it possible my MBP is defective?
 

fehhkk

macrumors 6502a
Jun 11, 2009
659
117
Chicago, IL
I just received my new 16" MacBook Pro (2.3 i9/32GB/1TB/5500M 4GB). I have an original UltraFine 5K purchased when I bought my 2016 MPB.

In clamshell mode (my normal setup), if I plug the UltraFine into the left side of my 16", everything works fine. However, if I plug it in on the right side, the display remains black.

If I run with the lid open and plug the UltraFine into the right side port, both screens continuously turn on and off. The actual display never appears on either, they just flash on and off.

I am using Apple's 0.8m Thunderbolt 3 cable.

Has anyone seen anything like this? Is it possible my MBP is defective?
Definitely do a PRAM reset: https://support.apple.com/en-us/HT204063

Mine works fine connecting the 5K display on any of the 4 ports.
 

Successful Sorcerer

macrumors member
Nov 23, 2019
67
14
I have recently got an older version 27MD5KA-B and 2017 MBP 15" top version and the computer is very slow, even just chrome web browser with 5-6 tabs and watching Youtube or Netflix. I guess video playback is kinda trigger of the problem.

I use it in clamshell mode and first I thought it's my laptop so did all "cleaning & optimisation" but didn't help then when I plugged out and use it as standalone laptop it runs perfectly no matter how many videos it's playing.

Anyone having this issue ?
Strange, I probably have the same MBP and no issues at all, everything runs smooth... 4k video, lot's of tabs etc.

Are people still seeing the wavy line issue with new displays? I saw one person noticed that one exchange didn't have the issue. Wondering if that's a one time thing, or if people are getting displays now without the wavy lines.
Just got this display (the new version) and no problems at all.
 

likegadgets

macrumors 6502
Jul 22, 2008
430
78
US
I have dual LG5K monitors (1st edition). When I had a MBP 2016 - I had random wake problems with one or both monitors requiring reboot. Then I had a 2018 MBP with a Vega 20 and the sleep problems went away. For a year there were no issues (including Catalina). I now replaced the MBP with a 2019 MBP 16" configured with the AMD Radeon Pro 5500M 8 GB, and the wake issue, mostly with the left side monitor has returned (and is random - not every sleep). Unplugging ad replugging works, but I have USB devices connected to the back of the monitor that cause problems, so requires a reboot. Any ideas ?
 

Ener Ji

macrumors 6502
Apr 10, 2010
389
285
I have dual LG5K monitors (1st edition). When I had a MBP 2016 - I had random wake problems with one or both monitors requiring reboot. Then I had a 2018 MBP with a Vega 20 and the sleep problems went away. For a year there were no issues (including Catalina). I now replaced the MBP with a 2019 MBP 16" configured with the AMD Radeon Pro 5500M 8 GB, and the wake issue, mostly with the left side monitor has returned (and is random - not every sleep). Unplugging ad replugging works, but I have USB devices connected to the back of the monitor that cause problems, so requires a reboot. Any ideas ?
My troubleshooting approach would be something like this:
  1. Swap the Thunderbolt cables and test that for a while to see if it's possibly related to a cable.
  2. Then try swapping the USB-C ports that the monitors connect to, to see if it's isolated to a particular USB-C port.
  3. If the issue continues to be isolated to the "left" monitor, try moving all the connected USB peripherals to the "right" monitor, and see if that changes anything.
  4. If so, try unplugging each USB device one at a time (connect directly to the laptop if you absolutely can't live with out it) and see if you can isolate a specific USB device that might be causing the issue.
Basically, you're trying to isolate whether a cable, a USB device, or the monitor itself is at fault, and then you can focus your troubleshooting on the offending component.
 

likegadgets

macrumors 6502
Jul 22, 2008
430
78
US
thanks for the tips.

My troubleshooting approach would be something like this:
  1. Swap the Thunderbolt cables and test that for a while to see if it's possibly related to a cable.
  2. Then try swapping the USB-C ports that the monitors connect to, to see if it's isolated to a particular USB-C port.
  3. If the issue continues to be isolated to the "left" monitor, try moving all the connected USB peripherals to the "right" monitor, and see if that changes anything.
  4. If so, try unplugging each USB device one at a time (connect directly to the laptop if you absolutely can't live with out it) and see if you can isolate a specific USB device that might be causing the issue.
Basically, you're trying to isolate whether a cable, a USB device, or the monitor itself is at fault, and then you can focus your troubleshooting on the offending component.
 
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Ailil

macrumors newbie
Dec 16, 2019
2
0
Hello everyone. I recently purchased an LG 5k and have realized that my iMac 5k is way brighter than the LG, its a really big difference, has anyone had this problem with kind of low brightness? if so how did you get it solved? did you get it replaced?
 

Successful Sorcerer

macrumors member
Nov 23, 2019
67
14
Hello everyone. I recently purchased an LG 5k and have realized that my iMac 5k is way brighter than the LG, its a really big difference, has anyone had this problem with kind of low brightness? if so how did you get it solved? did you get it replaced?
It shouldn't be a BIG difference, they operate both at 500 nits. So if both are set to the highest brightness they should be equal. I find the brightness of the LG 5K very good and a big plus over most monitors in the same pricerange which often have a brightness of 300-400 nits. Have no (brightness)problems with it. Do you you live near an Apple store where you can compare?
 

Ailil

macrumors newbie
Dec 16, 2019
2
0
It shouldn't be a BIG difference, they operate both at 500 nits. So if both are set to the highest brightness they should be equal. I find the brightness of the LG 5K very good and a big plus over most monitors in the same pricerange which often have a brightness of 300-400 nits. Have no (brightness)problems with it. Do you you live near an Apple store where you can compare?
I actually still have my iMac 5k and set it side by side with my lg 5k displaying different colors at full screen. I had to turn down my iMac 5k 5 levels to match the brightness. My problem is that sometimes my living room gets too bright and i dont have control over it so i need to push the brightness of my displays