@gprovost (how do I refer to a person/userid in this forum?) re: "how to debug"   I've had no further crashes after the two incidents ≈10 days ago. With little to back this up I suspect the issue is related Mac OS NSF client implementation with Armbian server: - the issues in my 10 months stable system started after I started working at home (due to the corona virus restrictions): I had my laptop NFS mounted to Helios for weeks - the two crashes took place when I was not