Try changing your Search User to: the actual username (DN). Try changing the Search Base to: OU=Kings College - Windows 7,OU=Kings College Guildford, DC=internal,DC=kingscollege,DC=surrey,DC=sch,DC=uknote: I have no idea if the spaces or - characters in the values will be an issue... but I changed my OUs to use _ instead of spaces a few years ago.