Backup with snapshot-policy being stopped

I am using in my VSS backups with the --snapshot-policy = on option I have noticed that at some point the backup is interrupted with the following message.
Could not find file …
How can I solve this?
Thank youduplicati%20vss

That looks like a temp file associated with Duplicati itself.

Are you using either the “Temporary files” Exclude option or “Exclude filter group” selection?

As for why it’s not there even though you’re using a snapshot, I’m not sure. With “On” the snapshot might be failing and just putting a warning in your log…

This setting controls the usage of snapshots, which allows Duplicati to backup files that are locked by other programs.

- If this is set to “off”, Duplicati will not attempt to create a disk snapshot.

- Setting this to “auto” makes Duplicati attempt to create a snapshot, and fail silently if that was not allowed or supported (note that the OS may still log system warnings).

- A setting of “on” will also make Duplicati attempt to create a snapshot, but will produce a warning message in the log if it fails.

- Setting it to “required” will make Duplicati abort the backup if the snapshot creation fails.

On windows this uses the Volume Shadow Copy Services (VSS) and requires administrative privileges. On Linux this uses Logical Volume Management (LVM) and requires root privileges.
Default value: “off”