Usernames you can't use in AD

We had a bunch of new hires this week and one user profile was giving us a bunch of issues. Whenever we logged on to our Terminal Services we would get strange errors that the profile couldn't load and that a temporary profile was being used.

After some digging, one of my co workers found out that you can't use 8 three letter usernames.

CON: — console (input and output)

AUX: — an auxiliary device. In CP/M 1 and 2, PIP used PUN: (paper tape punch) and RDR: (paper tape reader) instead of AUX:

LST: — list output device, usually the printer

PRN: — as LST:, but lines were numbered, tabs expanded and form feeds added every 60 lines

NUL: — null device, akin to /dev/null

EOF: — input device that produced end-of-file characters, ASCII 0x1A

INP: — custom input device, by default the same as EOF:

OUT: — custom output device, by default the same as NUL: