I have an Exchange 2010 server running on Windows Server 2008 R2 Standard, but now I want to setup a DAG, which I can't because the server OS is Standard. I understand that typically this requires a reinstall, but I ran across this microsoft utility (link below) that allows you to change your server OS version from standard up to enterprise. So my question is, is it safe to upgrade the OS with this method and trust that Exchange 2010 won't blow up and quit working? http://blogs.technet.com/b/server_core/archive/2009/10/14/upgrading-windows-server-2008-r2-without-media.aspx

I wouldn't do it. It has always been the case that doing anything to Windows with Exchange installed is not supported. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

Wouldn't do it either, and since you want to make a DAG it should be safe to assume you have a second server. Move all the users to that one and reinstall the first server. It does take some work, but its the safe way to go about it. /MartinExchange is a passion not just a collaboration software.

Agree with Both. "You can't upgrade Windows when Exchange is installed on the server." Details, Exchange 2010 Prerequisites http://technet.microsoft.com/en-us/library/bb691354.aspxFrank Wang

Agree with all of them, As Martin said, move the mailboxes to another server if there is any! and upgrade the Windows and reinstall the Exchange.Gulab | Skype: gulab.mallah

Agree with all of them, As Martin said, move the mailboxes to another server if there is any! and upgrade the Windows and reinstall the Exchange.Gulab | Skype: gulab.mallah