Regarding security in Windows server 2008

I am using Window Server 2008 R2 Enterprise edition and all the users logs on in the domain using their respective Mandatory Roaming Profile, and every user has a personal folder on the server, and everyone can access their own folders only but some time when a user logs on in the server the folders of the other users opened in a particular user’s folder and that user can cut, copy, paste or delete the data from that folder, All the securities policies are applied on the server, Please help me out on this