Okay, so we cannot plug in a Windows 7 Enterprise OS based flash drive and do an in-place upgrade of Windows 7 Professional.
This is important to note when it comes to any time quoting for things like replacing spindle based hard disks with Intel X25-M SSDs and expecting to drop the OEM default recovery on the SSD and then upgrade to Windows 7 Enterprise using the client’s Software Assurance.
Windows 7 Enterprise will always have a fresh install requirement if the base OS was Windows 7 Professional.
The Windows 7 Enterprise Upgrade version will upgrade certain prior Windows Vista versions though.
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book