With Remote Desktop Connection 6.1 (RDC) some things have changed.
That you now need to use mstsc /admin to connect to the console session is common knowledge….
However, when using .RDP files we used to add “connect to console:i:1″ in the .RDP to connect to the console session, well turns out that this no longer works….

Long stroy short, here’s what you need to do:

Before…
mstsc /console = “connect to console:i:1″ in .RDP file

After…
mstsc /admin = “administrative session:i:1″ in .RPP file