we are having windows 2000 DC, and the client connects to the computer on per server basis, and how it switched to per seat licenses i dont know,how can i switch back to per server license basis,

This forum is dedicated to the administration of Exchange, not Windows. You should post this question in one of these forums: Windows Server Forums Generalhttp://social.technet.microsoft.com/Forums/en/winservergen/threads Windows Server Forums Managementhttp://social.technet.microsoft.com/Forums/en/winserverManagement/threads In general this used to be true: Microsoft allows only one conversion from per server licensing to per seat licensing. It cannot be converted from per seat licensing to per server licensing. But I do think this information is obsolete by now. Check out the information Andy provides here about the Licensing service and the KB links: Trying to add Exchange Licenseshttp://social.technet.microsoft.com/Forums/en/exchangesvradmin/thread/b28954f1-c416-4090-87e7-56cdfda8ae66 MCTS: Messaging | MCSE: S+M | Small Business Specialist

Hi,To change licensing modes, open the Licensing console . On the Server Browser tab, expand the server, and double-click the server application. Select Per Seat, and click OK. Manu Philip Regards from www.windowsadmin.info