My LG 34UC88-B ultrawide display has a weird issue:
After the laptop goes to sleep – ~50% of the time, when the machine is woken up the display will not wake-up/power on.
My MBP (macOS) thinks the monitor is there but says there is no signal. From the window layout, I can tell that macOS thinks the display is up.
I can unplug/plug the cable into the same port multiple times and it will not "heal" without a reboot. If I plug the cable into a different USB-C port on the MBP – everything is normal.
I've also tried:
- Booting with a different PC – not had the issue although it's running Windows 7 in single monitor mode using a HDMI cable.
- swapping the cable (did not help)
I really hate having to move cables around every couple of days, so I'm wondering what else I can try?
How can I troubleshoot this further?
Best Answer
I'd start with resetting both the NVRAM and SMC (in that order). Before following the steps below, ensure you have no external hardware connected and that you're using the built-in keyboard.
Reset the NVRAM
Reset the NVRAM on your MBP as follows:
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).
Reset the SMC
Once you've reset the NVRAM and SMC use your MBP as usual and see how the display behaves. If it's still not waking up normally, then reset the SMC again but with the following steps instead:
If all of the above doesn't work, it may be worth testing your MBP in Safe Mode to see if it behaves differently.
Boot into Safe Mode
Follow these steps to boot your Mac into Safe Mode:
If the problem doesn't occur while booted into Safe Mode, let me know and we'll go from there.