Hi, Iam trying to install Exchange Server 2007 x64on a Windows 2003 R2x64 domain controller with SP2. But the installation prerequisite check tells me that there is no Windows 2003 with at least SP1 in the domain. How can this be solved? Some further information: The event log showsevent id2152 as described in KB 555854. In siminlair posts the problem was solved with a new user profile (see http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=1350971&SiteID=17), but the method described there did not help: Bondi Beach wrote: This is an RPC failure, due to DNS configuration errors or more likely COM permission restrictions. Try this (which assumes the admin account you were using for the install is configured to use local profiles): Log onto the machine using another account with admin permissions on the local machine. Delete the profile of the admin account you were using to do the install. Reboot the machine Logonusing the admin account you were originally using to do the install, thus creating a new local profile. Run setup again. Let me know if this fixes it. Thanks juergen998

Issue is solved: Download Exchange 2007 SP1 from http://technet.microsoft.com/en-us/exchange/bb330843.aspx. It is a complete slipstreamed installation SP 1 removes error event 2152. Furthermore the new error explanationgave us the hint to move the DC objects from an OU we created ourself back to the pre-defined "Domain Controllers" OU in the active directory structure.