creating a user in Active Directory: A device attached to the system is not functioning

Question

Consider this code attempting to create an Active Directory account. It's generating an exception here with a certain set of data. It's not clear right now what's causing the exception.

 var user = new UserPrincipal(someValidUserContext,
                              ".x-xyz-t-FooFooBarTest", "somePwd", true);

 user.UserPrincipalName = ".x-xyz-t-FooFooBarTest@foobarbatbaz.net";
 user.SamAccountName = ".x-xyz-t-FooFooBarTest";         
 user.DisplayName = "Some String 16 chars long";
 user.Name =  "Some String 16 chars long";
 user.Description = "Foo BarBaz 12 more characters";
 user.AccountExpirationDate = someDateInFuture;
 user.UserCannotChangePassword = true;
 user.Save();

 // exception thrown on Save(): 
 // A device attached to the system is not functioning

PrincipalOperationException was unhandled by user code: A device attached to the system is not functioning

What's causing this exception, and how can you work around it?

Answer 1

The sAMAccountName attribute must be 20 characters or less.