Backup of VM failed - disk image '/mnt/pve/.../images/.../vm-...-fleece-0.qcow2' already exists

[Luki20]

I turned on fleecing since some months ago. Works well, but I had to abort a backup job which was running lately. Since, the backup does not run again, because the fleece file already exists.

Is it safe to just remove it? When selecting in the storage pane -> VM disks and clicking remove it just says:
Cannot remove image, a guest with VMID '...' exists! You can delete the image from the guest's hardware pane

Is that a bug because I thought that a cleanup should happen?

Logs:

INFO: trying to get global lock - waiting...
INFO: got global lock
INFO: starting new backup job: vzdump ... ... ... --storage ... --notes-template '{{guestname}}' --notification-mode notification-system --mode snapshot --quiet 1 --fleecing '1,storage=...'

INFO: Starting Backup of VM ... (qemu)
INFO: Backup started at 2026-07-03 00:29:05
INFO: status = running
INFO: VM Name: ...
INFO: include disk 'scsi0' '...:.../vm-...-disk-0.qcow2' 500G
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: creating Proxmox Backup Server archive 'vm/.../2026-07-02T22:29:05Z'
INFO: enabling encryption
ERROR: disk image '/mnt/pve/.../images/.../vm-...-fleece-0.qcow2' already exists
INFO: aborting backup job
INFO: resuming VM again
ERROR: Backup of VM ... failed - disk image '/mnt/pve/.../images/.../vm-...-fleece-0.qcow2' already exists
INFO: Failed at 2026-07-03 00:29:05

Thanks!

 

[Impact]

Maybe a race condition or failed cleanup. Can you delete it manually?

 

[leesteken]

If there is no backup running then you can safely remove fleece disks. Older Proxmox versions often did not remove them automatically when a backup finished (with errors). More recent versions remove them automatically. I've seen this issue a lot in the past (but on ZFS storage) but not for some time. What Proxmox version are you running?

EDIT: In the past, I had to remove the fleece disks on ZFS manually using the command line.

 

[bbgeek17]

You can also try:
qm disk rescan [OPTIONS]

Rescan all storages and update disk sizes and unused disk images.

--dryrun <boolean> (default = 0)
Do not actually write changes out to VM config(s).

--vmid <integer> (100 - 999999999)
The (unique) ID of the VM.

That may bring in the fleece disk into config, although it may be a filtered out by code on purpose. If it brings it in - you will be able to remove it from the VM config panel.

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