Are you also running Duplicati Tray Icon? The .msi installer likes to install and start it unless told otherwise. Getting it to play nicely with Duplicati service install is a bit of work, but it’s sometimes nice to have there…
Prevent open browser when backup runs is the main reason I ask. There was some sort of odd interaction between Duplicati and the browser (I’d say the same for this post). So browsing to Duplicati starts backup?
–log-file and –log-file-log-level=Information or higher, added to a service reinstall, will make server log to file. Profiling is as noisy as you can make it. Best chance of seeing what happens, but creates a lot of output…