I ran across this as I tried to re-install VDF 17.1. Turns out the installed did not create the registry entry for "SystemMakePath". It only created the "SystemDFPath". Creating the "SystemMakePath" in the Workspaces reg key and filling in the data (I copied same from VDF17.0 which was working) changing all the 17.0 to 17.1 in the string value fixed the problem.