External display connection issues after waking from sleep mode.

Question

External display connection issues after waking from sleep mode.

Hi, I've recently bought a new MacBook Pro 16" and I have some issues with connecting it to my external display. I use my Mac as a workstation while connected to 49" Samsung monitor, with PictureByPicture feature (single monitor works as two separate). I connect to it with two USB-C to DisplayPort cables, which works perfect once connected, so I think the problem isn't in the cables (both high quality, not the cheapest ones).

The problem begins when I go for a coffee and my Mac goes for a sleep in that time, once I wake it up, only one screen is detected, and the second one is not. I have to reconnect one of the cables to make it detect that screen and work again.

It wouldn't be such a big problem since it's still working once reconnected, but as I'm a lazy bastard and I drink a lot of coffee during the day, my Mac also sleeps very often. Every time when I wake it up and it detects only one screen, my whole desktop configuration (window locations, window sizes and even windows opened in full screen mode) is gone and I have to reconfigure it after each coffee, and every morning as well.

The display itself shouldn't be the problem as well. I've used the same config with my old MacBook Pro 15" (Mid 2014) connected through Thunderbolt to DisplayPort cables and it had no issues at all.

It's pretty disappointing when you buy a top spec MacBook and you have so many problems just because of an external display. Especially when for the last 6 years you were thinking about MacBooks and MacOS that they're the most reliable hardware and software for your work.

Anyway, I would really appreciate any kind of help, suggestions or workarounds (if you know any).

Thanks in advance.

MacBook Pro 16″, macOS 10.15

Posted on Jun 17, 2020 10:27 AM

Reply

Answer 1

i_rina

Community Specialist

Jun 21, 2020 7:09 AM in response to fachowa_rynka

Greetings, fachowa_rynka!

Thanks for reaching out to the Apple Support Communities! It sounds like you're having an issue with your external display not waking properly when you wake your MacBook from sleep. First, check out this article to Reset NVRAM or PRAM on your Mac. Once you have done the reset, test to see if you have the same issue.

If you still have an issue, I recommend taking a look at this article with steps to follow for How to use safe mode on your Mac. This will perform checks and stop certain software from starting up automatically. Once you are in safe mode, test to see if you have the same issue.

Also, check out this article with steps for How to test an issue in another user account on your Mac to create a new user and test the issue in the new account to see if the issue is user specific or system wide.

Let me know the results and have a terrific day!

Reply

Answer 2

Jun 24, 2020 3:38 PM in response to fachowa_rynka

OK, the issue was with Moshi's 5K cable I've had. Another cable from different manufacturer solved the problem.

Reply

Answer 3

Jun 21, 2020 2:50 PM in response to i_rina

Thank you for your reply i_rina. Unfortunately, none of the articles helped. The ones with safe mode and testing with another user account I've already tried before. I've checked the option with NVRAM and PRAM but also no effect.

I think it's not a problem with the display anyway as my old MBP works without a problem, as well as my PC which I've tested last weekend. I've ordered another USB-C to DisplayPort cable which I'm gonna test once it's shipped as I feel it might be the issue.

Will let you know when I test a new cable.

Reply

External display connection issues after waking from sleep mode.

Similar questions