This is what you get for trusting a Microsoft Setup Tech called VHD-Boot. This technology is officially a supported Install Scenario from Microsoft. Those of you that follow this blog know I have raved and complained severally about this Tech. This is a single most frustrating support issue of Microsoft because you are allowed to Install OS with the tech, but you can never upgrade the OS to newest version since Windows 8.1. I still can’t place the reason for this. The picture you see here above is an attempt to upgrade a VHD-Boot of Win8.1U1 install to Windows10TP. Setup refused to upgrade it as you can see.
VHD-Boot like some of you already know is the convenience of VHD drive and the run speed of bare-metal install. You can safely call it a hybrid full-metal install and Virtual Machine install. The technology has a foot in each of both worlds.
The crazy thing is if I take this VHDx file and attach it to HyperV or any VM box, it will boot up and will be upgraded successfully. It is just for some unknown reason Setup cannot handle VHD-Boot upgrade. Knowing the tech behind VHD-Boot, it doesn’t look to me to be a rocket science to upgrade VHD-Boot drive. I mean, in the server world, MS is already servicing VHD drives offline. I wish I could find someone internally at Microsoft to shed light on the problem with VHD-Boot upgrade.
Anyway, now you know it , if you install any latest Microsoft OS in a VHD-Boot environment, you’re on your own to upgrade to latest OS. You have to do the dance of taking the VHD offline and attaching it to a VM and do the upgrade and re-attaching it as VHD-Boot. You are warned.