Symptoms
When you modify the group membership of an account in the Windows operating system, the modifications are reflected in
the subsequent execution of the SQL Server IS_MEMBER function only when:
You log off, and then log back on to the Windows 2000 client computer.You open a new connection and connect to SQL Server on a computer that is running Microsoft Windows XP or later versions.
Resolution
The security cache on the Windows 2000 operating system is updated only when you log on to computer. However, the security cache on Windows XP or later versions is rebuilt automatically.