Hi All, I am in the process of installing Exchange 2007 on a 64bit Windows 2003 R2 server. and then migrating our existing Exchange 2003 on to the Exch 2007. A bit on the backgroundand what i have done: Previously we had the Primary Domain Controller under a Windows 2000 server. we have moved all the FSMO roles from that server to a Backup Domain Controller (windows 2k3 server)and thenpromoted this BDC to the PDC. we have then decommissioned the windows 2000 server DomainController, so that there will be no Windows 2000 DCs in thenetwork. So currently on the domain, we have 1 PDC (Win2k3 SP2) and1 BDC (Win2k3 SP2). all the roles, including schema master are on the PDC. Once with all the preparation done we continuedwith/PrepareLegacyExchangePermissions and went through fine. this is followed by setup.com /PrepareSchema which ends with the following error: ------------------------------------------------------------------Start------------------------------- X:\Microsoft\Exchange2007>setup.com /PrepareSchema Welcome to Microsoft Exchange Server 2007 Unattended Setup Preparing Exchange Setup Copying Setup Files ......................... COMPLETED No server roles will be installed Performing Microsoft Exchange Server Prerequisite Check Organization Checks ......................... COMPLETEDThe Active Directory schema will be upgraded if you continue. Verify that the organization is ready for Exchange 2007 by running the Exchange 2007 Readiness Check, which is part of the Exchange Best Practices Analyzer. Configuring Microsoft Exchange Server Extending Active Directory schema Progress ......................... FAILED There was an error when executing 'ldifde.exe' to import schema file 'C:\WINDOWS\Temp\ExchangeSetup\Setup\Data\PostExchange2003_schema44.ldf'. Error code:8245. More details can be found in the error file 'C:\Documents and Settings\Administrator.INTERNAL\Local Settings\Temp\1\ldif.err' The Exchange Server setup operation did not complete. Visit http://support.microsoft.com and enter the Error ID to find more information. Exchange Server setup encountered an error. -------------------------------------------------------------- End --------------------------- I have looked into the ldif.err and found the following: -----------------------------------------------------------------------------Start------------------- Entry DN: CN=ms-Exch-Mobile-Mailbox-Policy-Link,CN=Schema,CN=Configuration,DC=internal,DC=pelion,DC=netAdd error on line 71: Unwilling To Perform The server side error is "Schema update failed: An attribute with the same link identifier already exists." An error has occurred in the program ---------------------------------------------------------------------------End-------------------- Can anyone please give some guidance on what I am doing wrong or missing out. Thanks in advance.

Hi, Check the following Microsoft KB Article, its for Exchange Server 2007 as well, as its mentioned in the "Applies To" section: Error message when you prepare an Active Directory forest for Exchange Server 2003: "Extending the schema in Active Directory failed" http://support.microsoft.com/kb/917682/en-us Please let me know if the above link did solve your problem. Regards, Alaa