When running Turnkey you will want to make sure that the user running the IIS Turnkey application and the IIS MDriven Server application has access to the file system. You do this by allowing the local user "IIS APPPOOL\{app pool name}" full control (create directories) access to the application root.

If you do not want to allow full control to the application root. The following may be an alternative

AppData - full control at application installation. You may limit to read/write access after installation and model upload is done.

Logs - read/write access ModeCodeAssemblies - only used for CodeDress

This applies both for MDrivenServer and Turnkey

This is particulare important when using CodeDress - since the assemblies need to be copied