Connected a Toshiba USB hard disk and after that a regular USB stick (on one of the front USB-C ports) for some manual file copies. When everything was finished I disconnected everything and suddenly my Monitor connected by Thunderbolt was going black and I had to long press the power button on my Mac mini to turn it off. But turning it on again still didn't display anything, the monitor didn't get any input signal. Turned the Mac mini and also the monitor off again and disconnected/reconnected the Thunderbolt cable from the monitor. After that and turning the Mac mini on again all was normal again. Weird.
But this time I didn't see any "SOCD report detected" error message. I didn't see any error message at all.
It COULD be the USB-to-USB-C adapter I'm using - but on the other hand it also happened when I connected a Samsung T7 USB-C hard disk. But file copy was always without problems. Weird behavior started after disconnecting the external media, not immediately but within a short period of time.
Nevertheless it seems only disconnecting external USB hard disks causing crashes - and not connecting one. While regular work or gaming no crash at all. I have an external Adata SE920 USB4 drive connected all the time without problems - but I can imagine if I unmount the volumes and disconnect the drive from the USB port the Mac mini could crash again.
Next time I'm using any external device I'll turn the iMac off when connecting and disconnecting. Let's see if that helps. But it's inconvenient as I often copy files to USB sticks...
The console shows (but don't know if this is related):
{"os_version":"macOS 15.2 (24C101)","bug_type":"115","timestamp":"2024-12-21 16:36:53.00 +0100","name":"Reset count","roots_installed":0,"incident_id":"2B2897DB-76E6-43FB-9C3D-E95EEA8E734F"}
Incident Identifier: 2B2897DB-76E6-43FB-9C3D-E95EEA8E734F
CrashReporter Key: 57209527-B575-4EF2-2201-132D321D0793
Date: 2024-12-21 16:36:53.09 +0100
Reset count: 0
Boot failure count: 1
Boot faults: rst btn_rst,btn_seq_reset target_off_restart
Boot stage: 0x40
Boot app: 0
socId: 6040
socRevision: 11