@otto & @JonMikelV, no I wasn’t prompted I chased it down as I was getting an error message when I first ran a job with VSS. As @kenkendk mentioned it was not a permissions issue, but something akin to the error in this GitHub post:
This lead me to realizing I was missing the Visual Studio C++ redistributable. I went with the 2017 version as it appears to be backwards compatible with older things that needed the 2015 version previously, and I saw a few posts that said newer versions of AlphaVSS needed the 2017 version. 2015 version might work just as good, but haven’t tried it.
I installed “directly as a service” from the ZIP version of Duplicati bypassing the normal installer, so that might be why VS C++ wasn’t automatically installed.
In any case, VSS permission issues are pretty painful to troubleshoot. There might be better articles out there, but this one is the first one I ran across that covers some of the troubleshooting steps I’ve had to do in the past to fix broken VSS on servers.