I have a late 2016 MacBook Pro with 4 USB-C ports and the LG UltraFine 4K Display that Apple is selling. So it is a USB-C to USB-C connection.

The monitor does not have an on/off button, argh. When I wake up the MBP, the LG display does not wake up. I have to go into Display settings of the Systems Preferences and detect new display every time. There is no info on troubleshooting in the documentation (the documentation on the monitor is not very detailed). Only that "The monitor will turn on automatically if the PC is operating normally."

Anyone have a similar situation or advice?

  • 2
    From the reviews on Apple's site (link you provided) this appears to be a consistent problem. The workaround is to unplug and plug back in. I've had similar issues with MacBooks and Dell Ultrasharp monitors which worked fine with other computers but failed to wake the display after going to sleep.
    – Allan
    Commented Jan 11, 2017 at 22:24
  • @Allan wow that was an awful blunder on my part. I'm removing my disgustingly incorrect comment.
    – NoahL
    Commented Jan 11, 2017 at 23:03
  • @NoahL - no worries...just here to help!
    – Allan
    Commented Jan 11, 2017 at 23:10
  • @NoahL Thank you. I saw the reviews after I posted this too. Wonder if they will have a fix for it or if I should consider returning it. Hmm. And thanks Allan too.
    – ispaany
    Commented Jan 11, 2017 at 23:42
  • 1
    Would recommend contacting Apple Support.
    – owlswipe
    Commented Jan 12, 2017 at 2:01

2 Answers 2


I had a similar issue. I have two UltraFine 4K monitors connected to a 2016 MacBook Pro. When the Mac went to sleep both displays went to sleep, but only one would wake.

This has been resolved by the latest firmware.

  1. Install LG Screen Manager. The LG site is still showing the old version.
  2. It will push the most recent version, v2.06.
  3. Upgrade your monitor to the latest firmware. (3.11, 3.4, 5226, 3.04, 0.2f)

For some unknown reason, LG appears to have removed the LG screen manager tool from their site. If you are looking for the latest firmware, it can be found via homebrew.

brew cask search lg
brew cask install homebrew/cask-drivers/lg-screen-manager
  • Worth noting that if you have 1 x 5K LG Ultrafine (27MD5KA) and 1 x 4K LG Ultrafine (22MD4KA), to apply the firmware updates you need to have them connected one at a time. Also, the firmware versions are different so don't expect them to be the same. My 5K is running on (3.04, 1.13,5237,3.04,0.1e) versus the 4K on (3.11,3.4,5226,3.04,0.2f) Commented Dec 7, 2017 at 11:30
  • 2
    LG Screen Manager now in the Apple App Store (for mac)
    – David H
    Commented Jun 10, 2019 at 21:32
  • Other LG monitors such as 32ud99 can be updated through "OnScreen Control" software which is available for OSX as well, specific version can be found on their website lg.com/us/support/software-firmware-drivers
    – Ivar
    Commented Dec 17, 2019 at 10:02

In addition to Allan's suggestion in comments, I would also try resetting your NVRAM.

IMPORTANT: The steps for resetting the NVRAM are different for the Late-2016 MacBook Pro models (i.e. different to all other Macs).

For all Late-2016 MacBook Pro models (with and without Touch Bar) follow these steps:

  1. Shut down your machine. Yes, a full shut down, not just logging out.
  2. Press the power button and then immediately press the commandoptionpr keys.
  3. Keep these keys pressed down for at least 20 seconds!
  4. Let go of the keys and let your Mac reboot normally.

Note: When you log back in you may need to readjust some of your system preferences (e.g. speaker volume, screen resolution, startup disk selection, time zone information, etc).


You should also try resetting the SMC. To do this on your MBP, follow these steps:

  1. Shut down your computer
  2. Keep the MagSafe adapter (power cable) plugged in.
  3. Press at the same time shiftoptioncontrol (on the left side of the keyboard) and the power button
  4. Let go
  5. Turn your computer back on with the power button.
  • I just tried this and it didn't seem to make a difference initially. Can you explain why resetting the NVRAM would make the external monitor work properly?
    – ispaany
    Commented Jan 12, 2017 at 2:02
  • I've just added instructions for resetting the SMC as well. Unfortunately, earlier I was having some connection issues and couldn't add these instructions in at the time. To answer your earlier question, NVRAM (Non-Volatile Random Access Memory) stores some of the settings of your Mac, some of which include screen resolution etc. The SMC (System Management Controller) looks after things such as power management including sleeping and waking up of the Mac, etc. That's why I've just come back to add this in as well, because your issue relates to waking up. Let us know how you go.
    – Monomeeth
    Commented Jan 12, 2017 at 2:39
  • I'd suggest trying the SMC reset before trying the NVRAM reset because the NVRAM reset is destructive to those system preferences. (SMC alone worked for me.) Commented May 22, 2017 at 8:10

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