M1 mac mini display keeps losing scaling

Ah, nice, Hammerspoon looks a lot easier to deal with than Sleepwatcher. And yeah you have to change the resolution out and back, or else the display system doesn't think there's any changes to apply (which is probably also why the manual System Preferences fix requires changing the scaling to something else before changing it back too).

Possibly, and issues like these are why I was hesitant to jump over to Apple Silicon so quickly since all first-gen Apple machines have problems like these. But I was due for an upgrade and didn't want to be stuck on Intel.

My monitor is connected directly via HDMI but I've also had issues with my Thunderbolt dock disconnecting on sleep, which causes the OS to complain about unsafely disconnecting my Time Machine volume (which is connected via that dock). I haven't had any trouble with the USB-A ports, though, or with my directly-USB-C-connected NVMe drive.

How did you install displayplacer? If you're getting "command not found" it means that it's not in your execution path. If you didn't install it using homebrew, try putting it in /usr/local/bin (which you can open in Finder by running "open /usr/local/bin" from Terminal).

Just closing the Hammerspoon window should be enough to make it run, yes. Also if you open the console you can see what error is happening when it tries to run. If you put displayplacer in a different location you'll need to change the script to point to it as well. The script I provided assumed you used Homebrew to install it (thus /opt/homebrew/bin) but if you put it in /usr/local/bin then it'll need to be /usr/local/bin/displayplacer.

Unfortunately, it seems that my monitor doesn't come up as supporting HDR when it goes through my Thunderbolt dock (even though it lists the HDMI port as being HDR-capable), and when my monitor is connected as SDR, the color profile is entirely unacceptable. So, I guess I'm just going to put up with this bug for a while longer. Hopefully it gets fixed by 11.3.

These are the kinds of things that happen with new hardware and software platforms. Generally it takes time for weird issues like this to shake out.

Personally the M1 has been quite stable for me, and the number of issues I’ve had have been surprisingly few. This M1 mini has been WAY more reliable than the Intel iMac it replaced, anyway. But different people have different experiences with things.

Ah, I'll check that out! I used to use SwitchResX but I didn't like how invasive it was and it never seemed to do quite what I wanted anyway (so I never even bothered to check if it would work on the M1 or Big Sur), and this looks like a much better tool for what that does anyway.

Then I'll give it a try, but I suspect that the display going to sleep is the problem, not the computer going to sleep, given how the Mac is reconfiguring the displays when the monitor is power-cycled.

Okay, those sound like pretty serious problems to me. I haven’t experienced anything like that, but those problems would be very frustrating to me as well.

But this forum thread is about one specific minor problem I have been having, and I would appreciate it if people would stick to discussing this problem. I’m sure there’s threads about the problems you’re having, and they also sound serious enough that you should be talking directly to Apple support and maybe returning the computer as defective.

In any case, don’t attack other users for not having the same problems as you or bot being aware of the problems you’re having.

The id:xxxx-xxxx should be replaced with the ID of your monitor, which you can get by running "displayplacer list" from the command line. If you only have one monitor you can leave the entire id:xxx-xxxx-xxxx off.