Another way is run it as a service:
As my little experience duplicati works fine with VSS even if a couple of times I obtain a warning from backkup job but this happen because the backup job start running while OS made a snapshot (in my system I scheduled a task who create new snapshot every hour - so duplicati should backup data up to date).
If I understand correctly duplicati can’t create a snapshot before start a backup job but only access to the most recent snapshot available. Can anyone confirm this?