FULL PRODUCT VERSION :
java version "1.6.0"
Java(TM) SE Runtime Environment (build 1.6.0-b105)
Java HotSpot(TM) Client VM (build 1.6.0-b105, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.0.6000]

EXTRA RELEVANT SYSTEM CONFIGURATION :
Corporate computer part of a Windws NT domain.

A DESCRIPTION OF THE PROBLEM :
The system property user.home is wrong. If my login name is xxxx, the user.home directory should be c:\Users\xxxx on Vista. Java gets the user.name right, but the user.home is different: in my case it uses the domain guest account, which I have no clue how it gets to that! It might just be that it is the first directory found in C:\Users.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
1.6.0
xxxx
C:\Users\xxxx

ACTUAL -
1.6.0
xxxx
C:\Users\DGUEST

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class TestUserHome {
  public static void main(String[] args) {
    System.out.println(System.getProperty("java.version"));
    System.out.println(System.getProperty("user.name"));
    System.out.println(System.getProperty("user.home"));
  }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Force the user.home system property to the correct as a -Duser.home=... argument to the JVM.