I currently have an exchange server with service pack one installed and i am trying to evaluate whether or not to install sp3 and also the best way to go about doing so. I am under the impression that you can install SP3 without installing sp2 first (go straight to sp3 from sp1). Is this true? Also i am somewhat gun shy because of the prep for active directory. I currently have three domain controllers, one is server 2008 and the other two are 2003 R2 servers. Are the changes to active directory schema in addition to the changes made when i introduced the 2008 DC? Does anyone know of any issues with AD after the prep for SP3?