Administrative processes, including CMD, don’t see mapped drive letters anymore, unless you do this:
https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/ee844140(v=ws.10)
In this registry area:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
create DWORD EnableLinkedConnections, value of 1.