[Today’s post comes to us courtesy of Damian Leibaschoff from Commercial Technical Support]
During the operating system portion of the Small Business Server 2011 Standard installation, you will reach a screen that asks what type of installation do you want. The options here are two: Upgrade or Custom (advanced). You can only use the Custom (advanced) option to successfully install SBS 2011 Standard, there is NO in-place upgrade path from previous versions of Windows or SBS.
SBS 2011 Standard is built on top of Windows Server 2008 R2 Standard and this is a behavior that derives from that integration.
If you want to add SBS 2011 Standard to a network where SBS already exists, you will need to follow the migration documentation found here: http://technet.microsoft.com/en-us/library/gg490796.aspx. This documentation will also help you add SBS 2011 Standard to an existing domain where there is no SBS product currently in place.