2008, Exchange 2007, SP1, head going to explode....

For those looking to install Exchange 2007 on Server 2008, you have do doubt run into the fact that only the SP1 version of Exchange 2007 is supported on that platform.  This leads to a conundrum for those of us raised on the previous versions of Microsoft Exchange, namely how do you install the Release to Market (RTM) version of 2007 onto server 2008 in order to do the SP upgrade?

The short answer is, you don't.

The long answer is, you can go ahead and toss out your RTM Exchange 2007 disks with the trash, you don't need them anymore at all.

Microsoft has started a new trend with Exchange Server 2007, namely slipstreamed Service Packs that no longer require at least one previous version be installed first.  When you download the Service Pack Binaries from here, you will notice that the overall package size is gigantic compared to SP's from other platforms. That's because the original binaries - updated where necessary for SP1 - are also in that package.

In short, you can have a perfectly new Server 2003 or Server 2008 box, download only the SP1 version of Exchange 2007, and do the entire install from the SP1 version of the bits, no need to install the RTM first.  This is how you get around the fact that only SP1 is supported on Server 2008, just install only the SP1 bits, and you get the whole package at once, already updated.

You still have to have a valid activation key if you are installing from scratch, even if you use the SP1 bits, so be ready to type it in when requested or you're stuck with a 180 day trial timer.

The good news is that it looks like Microsoft will be pre-slipstreaming other applications SP's as well.  This will make life a great deal easier when you need to install an application from scratch, especially for those - like me - who can never seem to get the slipstreaming process to work correctly no matter what tools they try!