mac mini tries to find a mouse

Hi, guybeaux, this is a known thing, if you use Bluetooth mice and keyboards, especially on startup, login, and for troubleshooting, they tend to be iffy/ problematic/hit or miss.... If you're using a Magic mouse, or any other Bluetooth mouse that comes with a cable to connect it to your Mac/PC, while starting up, make sure the cable is plugged into the mouse and then into your Mac/Mac Mini/PC and that the mouse itself is fully charged up.... If you have mouse with a little reciever dongle, you can use that, rather than bluetooth for startup/login/troubleshooting, it's more reliable, not 100% more reliable, just less iffy.... even on mine, on startup, sometimes I have to turn off, wait a bit, and turn on the mouse itself, and unplug, wait a bit, and then plug the little reciever dongle back into my USB port/socket. That usually fixes it.... I see you don't have an M1 Mac Mini, so you can do this: reset smc/pmu and zap pram 4 times on startup.... it's a general fix for when things aren't working quite rigfht and you don't know exactly why...anyways, see link:

https://www.macworld.com/article/224955/how-to-reset-a-macs-nvram-pram-and-smc.html

the zap pram part of it should be done at least 3 times on startup, then let go and let your mac mini boot up as usual. If you need a working mouse and keyboard on startup/for troubleshooting, and we all do, right....then just get yourself a USB wired keyboard and mouse to use as a spare one or for troubleshooting. Doesn't have to be a "Mac" keyboard + mouse....just so long as it's USB and wired it should work OK, Mac or PC, doesn't really matter

hope this helps

John b