When using Remote Desktop Connection, you can get a popup window asking for your login credentials before a connection to the remote machine is made. When it works, you can use these credentials to bypass the remote machine’s authentication screen and login directly. However, this popup can cause a login failure if the authentication methods don’t match, or be very annoying if you want to login to test machines using a range of account usernames, or accounts with no password.

By adding the following line to the end of a *.rdp file, the credential popup will be disabled and you can login using the remote machine’s login screen instead:

enablecredsspsupport:i:0