That's a new piece of the puzzle which might be significant. I would be looking at the details of your user's logon process. It may sound odd, but I have had situations where people have had problems arising from names which use accented or non-alpha characters (eg Éclair, Will O'Wisp, Mac-Burger) or even a hard space in their name. Another way-out idea is to check whether their logon inadvertently uses a reserved word (Mr David Elete might need to be careful about how he writes his name!!!)