You’ll find the old config in C:\Windows.old … one of the downsides to running as a service during a major Windows update. See this post for more info:
This is probably because of the latest Windows 10 Spring Creators Update (1803).
If the service is running using the LOCAL SYSTEM account (this is the default account for starting services), the user profile folder is located in C:\Windows\System32\config\systemprofile.
Duplicati stores its configuration and local databases in a subfolder of this location (C:\Windows\System32\config\systemprofile\AppData\Local\Duplicati or `C:\Windows\System32\config\systemprofile\AppData\Roaming\Duplicati).
T…