Rename Credential.Name to PrincipleName. PrincipleName comes from the security service provider, which may not correspond to the domain user name. For instance, if I'm using kerberos on my domain, my principle may be user@DIVISION.CORP.COM, meanwhile my username might be CORP\user.

NSspi/Credentials/Credential.cs

@@ -72,7 +72,7 @@ namespace NSspi.Credentials
         /// <summary>
         /// Returns the name of the principle of the credential.
         /// </summary>
-        public string Name
+        public string PrincipleName
         {
             get
             {

NsspiDemo/Program.cs

@@ -33,11 +33,11 @@ namespace NSspi
                 clientCred = new ClientCredential( packageName );
                 serverCred = new ServerCredential( packageName );
 
-                Console.Out.WriteLine( clientCred.Name );
+                Console.Out.WriteLine( clientCred.PrincipleName );
 
                 client = new ClientContext( 
                     clientCred, 
-                    serverCred.Name, 
+                    serverCred.PrincipleName, 
                     ContextAttrib.MutualAuth | 
                     ContextAttrib.InitIdentify |
                     ContextAttrib.Confidentiality |

TestClient/ClientForm.cs

@@ -66,7 +66,7 @@ namespace TestClient
             this.connection.Disconnected += connection_Disconnected;
 
             // --- UI Fillout ---
-            this.usernameTextbox.Text = this.cred.Name;
+            this.usernameTextbox.Text = this.cred.PrincipleName;
 
             UpdateButtons();
         }

TestServer/ServerForm.cs

@@ -66,7 +66,7 @@ namespace TestServer
 
             UpdateButtons();
 
-            this.serverUsernameTextbox.Text = this.serverCred.Name;
+            this.serverUsernameTextbox.Text = this.serverCred.PrincipleName;
         }
 
         private void Form1_FormClosing( object sender, FormClosingEventArgs e )