While trying to move a VM from one node to another I got the error message:
VM 100 qmp command ‘blockdev-snapshot-delete-internal-sync’ failed – Failed to get a snapshot list: Operation not supported
One snapshot was stuck and the VM locked. How to solve this?
qm unlock 100 qm listsnapshot 100 qm delsnapshot 100 preFirstBoot --force
qm unlock <ID> qm listsnapshot <ID> qm delsnapshot <ID> <snapname> --force
it might be that the snapshot will remain on the hard disk.
Happy unlocking :)