@@ -81,8 +81,9 @@ func (cli *DockerCli) configureAuth(flUser, flPassword, flEmail, serverAddress s

 	if !ok {

 		authconfig = types.AuthConfig{}

 	}

+	authconfig.Username = strings.TrimSpace(authconfig.Username)

-	if flUser == "" {

+	if flUser = strings.TrimSpace(flUser); flUser == "" {

 		cli.promptWithDefault("Username", authconfig.Username)

 		flUser = readInput(cli.in, cli.out)

 		flUser = strings.TrimSpace(flUser)

@@ -91,6 +92,10 @@ func (cli *DockerCli) configureAuth(flUser, flPassword, flEmail, serverAddress s

 		}

 	}

+	if flUser == "" {

+		return authconfig, fmt.Errorf("Error: Non-null Username Required")

+	}

+

 	if flPassword == "" {

 		oldState, err := term.SaveState(cli.inFd)

 		if err != nil {

@@ -104,7 +109,7 @@ func (cli *DockerCli) configureAuth(flUser, flPassword, flEmail, serverAddress s

 		term.RestoreTerminal(cli.inFd, oldState)

 		if flPassword == "" {

-			return authconfig, fmt.Errorf("Error : Password Required")

+			return authconfig, fmt.Errorf("Error: Password Required")

 		}

 	}