Cannot map to any network drive or shares/RPC server is unavailable

For me it was missing one registry key
REG_DWORD "DhcpNodeType" = 1
under
HKLM\SYSTEM\CurrentControlSet\Services\NetBT\Parameters

A easy trick is, if it worked before, you can look under
"HKLM\SYSTEM\ControlSet001\Services\NetBT\Parameters"
or
"HKLM\SYSTEM\ControlSet002\Services\NetBT\Parameters"
and compare the difference.

This also fixes an issue opening Group Policy Management showing "RPC server is unavailable"