16" MBP 2019: Graphical glitches followed by crash when lid closed
I have been trying to find a solution to this problem for months, but so far no luck. Hoping to have some success here.
I have a 16" Intel MacBook Pro (2019), running connected to an external monitor. It's connected to the display, and everything else, via a CalDigit TS3 Plus dock. Works well.
However my desk is a little small and this laptop is really big. I got a Twelve South BookArc vertical stand for it.
When I close the lid on the MBP and engage clamshell mode, and put it in the stand, it works well usually for a few hours. Then I start getting some graphical glitches appearing on the screen. They appear as a series of small squares, usually green to blue in color, arranged in diagonal lines:
It doesn't affect the performance of the computer at all. If I take it out of the stand and open the lid, they go away. If I don't eventually the system completely freezes and becomes unresponsive and I have to hard reset it.
A few observations:
- I don't think this is heat related. This can happen even when the computer is almost idle (just web browsing).
- As can be seen above, the glitches show up on a screenshot. Not sure if that rules out the cables and/or graphics card but thought it was worth mentioning.
- I ran Apple Diagnostics on this computer and it found no problems.
- I have another laptop, a 2020 13" MBP, which works without issue in the stand.
Possible ideas?
- Could it still be heat related? I still find this doubtful since MacBook Pros are designed to run with the lid closed, also in the stand the laptop is vertical which allows for more airflow.
- Could it be an issue with the dock? I don't have another dock to test with.
- Other suggestions?
MacBook Pro 16″, macOS 11.6
