Apologies if this is a straight forward question, just seeking some clarification. I am currently working in a remote region and will only have time on this visit to update the organisation's AD schema in preparation for Exchange 2010. There is a single Exchange 2003 server in the environment and a 2003 AD. My plan is on this visit to upgrade the schema in preparation for Exchange 2010 server deployment later. The reason for the delay is to ensure that there are no issues that arise from the AD update. Are there any potential problems or issues with having an updated Exchange 2010 AD schema without an Exchange 2010 server in the environment for an extended period.

Never ran into AD issues with the update from 2003 to 2010. You should be fine.

All the schema updates do is add support for Exchange 2010 to the domain. Its like having a building with the space, but not filling it. Therefore running prep on the Forest and the domain isn't an issue. If the site is a single forest single domain, then you don't have to run prep in advance anyway. The GUI installer will do the update for you before installing the product. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi As far as I know, article of technet explains it clearly. Prepare Active Directory and Domains BTW: windows 2003 sp1 AD schema is enough for exchange 2010.

Thank you all for the info and quick reply, much appreciated. Ran the GUI setup tonight and it failed initially on the AD upgrade process. Turned out to be a trailing space on one of the recipient policies. After resolving that, installation completed sucessfully.