Macbook Pro 16" with UltraFine 5K display not waking from sleep

Having the same issue with an external display (LG UltraFine 5K Display) where sometimes the MacBook Pro doesn't recognize that it has the display connected to it. This is usually when it wakes from an extended sleep. I have to restart the MacBook Pro, disconnecting and reconnecting the cable doesn't seem to help. It is connected via the Thunderbolt 3 cable that came with the display (uses one cable to charge and feed video). I have the display set as my primary display with menu and the MacBook Pro is the secondary display. Prior to this display I had the original Apple Thunderbolt Display that I connected with an adapter. Same thing was happening, so I thought it was the display and adapter, which is why I purchased the new display. I have swapped the supplied LG Thunderbolt 3 cable with the Apple Thunderbolt 3 cable. Same thing happens.

Our setups are very similar - only difference is that I have the 8GB graphic card, see my setup below:

Purchased in December... 16" MacBook Pro

• 2.3GHz 8‑core 9th‑generation Intel Core i9 processor, Turbo Boost up to 4.8GHz
• AMD Radeon Pro 5500M with 8GB of GDDR6 memory

I ran a 2017 15 inch MBP with the LG Ultra fine 5K display without any problems.

Besides the cannot wake from sleep problem the 16 inch also has problems with scrolling menus. They tend to blank out while scrolling.

So far - no solutions but I think Apple should stop advertising that this computer is built to run multi 5K monitors!

I'd change that statement a bit; "Apple should stop advertising that this monitor is built to work with Mac."

It's had so many issues since being put out in 2016. The computer still works great with all three Apple Thunderbolt displays I have. I did a test earlier today by using both my Thunderbolt Display and the LG Ultrafine. Sure enough the Thunderbolt display wakes up just fine and the LG Ultrafine 5k won't wake up (like the rest of this thread)

I have major issues with the LG Ultrafine displays as well, and it has been degenerative. I have two of these displays, but usually only use one. for the first several weeks I had zero problems. Then after updating the OS (I think), I started having problems with screen flicker (both built in screen and LG), and sometimes the LG just wouldn't come on at all. Switching to a different side of the MacBook fixed the issue temporarily. It seemed to get worse and worse, and now no matter what I do, and no matter what port I use, my MacBook cannot drive the LG Monitor at all. And if I do plug in the monitor while my MacBook is awake, I get screen flashing (on the MacBook), and sometimes a system crash/restart. If I plug it in while the MacBook is asleep, it will charge the MacBook, but no LG display at all. I've swapped monitors, reset PRAM, SMC, etc. No change. My MacBook has very little on it since I went with a fresh setup rather than restoring a backup from my previous MacBook. I have the Adobe Suite, Office, and a couple other small apps - TeamViewer, Magnet, and that's about it.

Many thanks for letting us all know that your new MBP 16 did not solve the problem. I have spoken with someone else who has a new MBP 16 and uses it on two different monitors (not LG) and is having the same problem. He thought it was his cables, so went out and bought new cables. I don't know if this helped him.

What I have found is that I can now sleep my Mac, wake it up and then sleep it again. On the 2nd wake up it seems to wake up the monitor.

Now if only Apple would wake up and repair the problem :-).

Thanks for all the helpful research... I agree, which is why I was reluctant to take my MBP in. Takes time to setup and I didn't want to go through the hassle of having to do this again. Seemed too wide-spread to be specific to my MBP. So we are all waiting on Apple. Everyone should at least log a support call or chat with Apple to show them this is a wide-spread software/hardware specific problem and not a user's MBP.

I've seen similar issues as well. Again I am using a single LG 5K Ultrafine at home (have 2), and an HP 24 4K at work (have 2 also). Even with one of these monitors I have these issues. They get worse the longer it's been since a restart. And I have noticed that even when the monitor is seemingly working fine, If I plug in a USB C external drive or something like that, and start doing any kind of file copy or anything, the external monitor starts randomly flickering. Then sometimes moving it to the other side of the MacBook stops it (but not always). I thought maybe it was an issue with not enough power coming into the MacBook from the monitors. I tried plugging in my power brick while connected to the LG monitor, and my MacBook crashed... It also almost always freaks out or crashes if I unplug from the 4K monitor at my office and go home and plug into the 5K. That almost always requires a restart... So glad this $5K laptop is costing me so much productivity...

Exact same problems with Dec 2019 Macbook Pro 16 2.3 Ghz 8core i9, 32 GB ... w/ Apple Care and macOS 10.15.3

Apple support had me do the exact same procedures and which I was pretty sure was not going to fix the problem.

Additionally when the wake up the Macbook Pro when connected to the LG 5k it hard crashes, reboots with a Bad Magic! error, no additional errors in the log. This is frustrating with expensive hardware to have a problem and not patches yet... hopefully a patch will come out soon.

Slightly different issue with the Macbook Pro 16" and the LG 5K monitor. After sleep mode the monitor does come back but the resolution drops down from the 5120x2160 to 3000 something. Removing cable and plugging back in resolves the issue. Doens't seem to happen everytime. Still using the LK supplied cable to drive video and power.

I have the same issue, and just as others have mentioned, I tried all methods to reset all types of settings. Additionally I have firmwares and OS updated. In my case, my issue shows in both of my LG Ultrafine monitors: a 5K one from 2018 and a 22" 4K one from 2016.

My 16" Macbook Pro has the AMD Radeon Pro 5500M with 8GB VRAM. The issue does NOT happen with a 2018 15" Macbook Pro with i9 and Radeon Pro 560X.

Hi Pommedan, thanks for the suggestion, tried both and the display is still blank (not on), however I can always use the keyboard and mouse which are connected to the display. The problem has gotten worse were the display does not come out of sleep but the MBP does after the laptop is in sleep mode for a while. I can reproduce the problem when locking the MBP and watching the displays go blank in a few minutes. The laptop / MBP display comes on, however the LG5k external monitor does not. I can wake the computer with the attached external keyboard and mouse which is connected to the LG5K monitor and that is connected over a single Thunderbolt cable to the MBP.

This isn’t just LG5Ks doing this. We’ve seen problems with 4K monitors and some have even mentioned other USB-C devices, like drives, etc. I also tried using my power brick with the LG5K and it crashed my MacBook.

that's exactly the problem I have. 16" MBP with a LG 4k Ultrafine (first one that came out). Machine wakes up ok (as long as its not connected to an eGPU), and my third HD monitor connected via a display port in a hub wakes up, but the LG only wakes up if I unplug and replug. Every time.

Not exactly, but it sounds similar/related. With mine, I have no problems at all soon after a restart. I can usually sleep/wake, and unplug/replug without issue. But after it has been running for a while, sleep/wake and unplug stop working, no matter what I do. And after it has started happening, nothing fixes it except a restart. If I continue messing with it after the external display doesn’t wake up, I get screen flashing (on and off) with both screens, and eventually if I’m keep trying to unplug/replug, the MacBook will usually return to the login prompt, as if the finder has crashed and restarted. While I am experiencing these strange external screen issues, other external devices also seem have problems.

One thing that might mean something to someone is, my sleep/wake problem seems to be much worse when I switch displays. I might go a couple days on an LG5K with no issues, then change my location and connect to an HP4K and have problems. Restart and it’s fine for the day. Change locations and connect to an LG5K, and the problem is back. The switching might not have anything to do with it, but maybe...

Also just in case anyone is curious, I do use scaled resolution settings instead of the defaults.

I've followed and also commented on this thread with the same wake from sleep issues... originally I connected the Apple Thunderbolt Display to the 16" MBP and experienced the wake from sleep issue which is why I purchased the LG monitor (from Apple Store). Updated to 10.15.3 and still experienced the same issue. Lately it has been fine, although I did experience a color shift (display and MBP colors were over-saturated) on one wake and had to restart to resolve. For me, when it happens it is usually after an extended sleep (overnight), the MBP flickers and the LG display is blank. I can't see anything on the MBP to open the systems preferences to try and "detect displays". I have not tried closing the MBP lid and seeing if that helps. I have had to hard restart by holding the power button. I do not mirror displays, I have the LG as the main display with the menus and use the MBP as the secondary display to move apps to such as mail or messages. I purchased the MBP and LG in December (not sure which version of the LG display I have, I will have to check tonight when I am home). Prior to the 16" MBP, I had a 3 year old 15" MBP and the Thunderbolt Display worked flawlessly. The wake issue happened within a day of receiving the MBP and connecting to the Thunderbolt Display. I traded in the the 15" MBP and sold the Thunderbolt Display so I cannot test anymore.