

Nothing will compel it to come back to life and rebooting just sits there. Oh, and every few weeks Finder will just give up and die, which has the interesting effect of preventing the Feedback application from gathering logs. Luckily this was something I could fix on my own. I had to create a custom EDID with known good values for it to work properly. My monitor isn't correctly detected when using an eGPU, but it works fine with Thunderbolt. Probably because windowserver goes nuts with CPU usage. Not on Sidecar itself, which is actually really snappy, but it brings everything else to its knees. The AirPlay icon in the menu bar also flashes between Sidecar, Airplay, and nothing at all. When I look at the logs, AMDRadeonAccelerator is going nuts. I'll randomly get intermittent freezes where the display stops updating and user input stops being accepted. Most of my problems seem to revolve around using an eGPU with the laptop shut.

I’ll see if I can delay it until 10.16 is out and will pray that they started to prioritize bug fixes again, but I have little hope that’ll actually happen. I dread switching to 10.15 unfortunately, I will get a new MBP 16” from work, which normally I’d relish, except that there seems to be no way to use it with anything but 10.15. but starting with 10.9, too many issues made this undesirable). Before that, I went from 10.8 to 10.11 before that, I never missed a release, often was running beta of the OS etc. This is horribly annoying, and didn’t happen to me before (in 10.11 I skipped 10.12 and 10.13, for reasons similar to the OP.

And I have dozens or hundred of them open. Much worse is that sometimes (once a month?) during this process macOS completely messed up all my open windows: they are all resized to a tiny size. Have not yet found out a reliable way to resolve this, but I usually manage with turning the monitor off and on again and/or unplugging/replugging it, possibly a couple times each. Now, sometimes (once a week?) when I plug it into the external screen, it just won’t wake up, unless I open the lid, and then it still won’t recognize the external screen. MBP: I usually run the laptop with closed lid and an external screen at work and at home and use it in “laptop mode” during my commute. While I don’t have that particular issue, I have other issues related to external screens, with 10.
