Veeam backup-proxy fails to reach hypervisor, can't deploy backup proxy

[nleistad]

This has worked for nearly a year, then I noticed backup-worker missing on a node. Went to re-deploy worker and get:

1/30/2026 9:13:30 AM Failed : Failed to deploy the worker VM: Failed to reach the hypervisor. Error output: unable to create VM 104 - unable to open file '/etc/pve/nodes/"host1-of-3"/qemu-server/104.conf.tmp.30581' - Device or resource busy (0:00:02)

1/30/2026 9:13:30 AM Failed : Worker backup-worker-elkhorn test failed: Failed to reach the hypervisor. Error output: unable to create VM 104 - unable to open file '/etc/pve/nodes/"host-1-of-3"/qemu-server/104.conf.tmp.30581' - Device or resource busy

I can deploy new backup proxy to the other hosts without issue.

I can drop to command prompt on Veeam-Console and ssh root@IP-of-host-1 without issue.
I can touch files in /etc/pve/nodes/"host-1-of-3"/qemu-server/ successfully as root. There are NO *.conf.tmp files conflicting in directory.

Starting here rather than Veeam as it worked before and works on other Proxmox hosts in cluster. If Veeam is a better avenue, please advise.

Thanks.

PVE v9.1.4, Veeam 13.0.1.1071 (on Windows Server 2022)