I’ve tried everything suggested several times (using “qvm-start $vm; sleep 10; qvm-shutdown $vm”), including the obsolete VMs I haven’t gotten around to deleting yet. No change. I found a somewhat similar topic (Fedora Template cannot be cloned) and the issue that it referenced (Template cloning in R4.1 is significantly slower than in R4.0 · Issue #6329 · QubesOS/qubes-issues · GitHub). My installation is using the “file” pool. I can’t see anything wrong with my setup, based upon those threads.
I installed the system on 2018-04-21 and have been diligent about updating it.I am now fedora-33 and debian-10 as template VMs (and archlinux). I cannot find any logging about which VM(s) it is complaining about. I have started the process of excluding individual VMs from the backup, with no luck so far. I have also tried reinstalling any dom0 qubes-* package which looked like it may be relevant.
I haven’t gotten a successful backup since 2021-01-01, and I have updated a lot since then.
How can I find out which VMs/files/etc are considered to be “dirty”?