I have a tricky site setup that looks like this. root directory = WordPress installation 1 library = WordPress installation 2 forum = SMF All the login, registration, logout and change password is handled by the forum with a little bit of a custom script. It uses XML-RPC to speak to the wordpress installations. Registration, logout, change password works all ok. Login doesn't. Even though all the cookies have been set, for some reason the user does not get logged into the wordpress sites. Any idea what I need to look at?