A common way to add domain groups to the local administrators group on a computer is with the
net command. This worked well for me until I ran into groups with names longer than 20 characters. That’s right, the NET.EXE /ADD command does not support names longer than 20 characters. If
net localgroup /add is being used in a computer startup script, the groups with long names just won’t be added.
So the traditional batch file startup script was replaced with a PowerShell startup script, and this is how I now add domain groups to the local administrators group on computers.
([adsi]"WinNT://./Administrators,group").Add("WinNT://DOMAIN/My Extremely Long Group Name with Spaces,group")