RDC error "terminal service exceeds number of connections"

If trying to remote login as Administrator to a remote MS computer via Remote Desktop gives an error about too many open connections, do the following:

1. open cmd.exe on your local Windows machine

2. Run from command line:
mstsc /admin

This will run Remote Desktop and allow the login.

optional - 3. Open Task Monitor on the remote computer and 'logoff' all the logged in users but yours.