Had an interesting dilemna the other day. I had a HP DL360 G5 system already loaded with Windows 2008 server and hyper-v. However, I wanted to put the free, hyper-v r2 core on there instead. About half-way through the installation, I received an error that windows installation cannot proceed.

Ok. I tried it again, failed. I tried new media, failed. I reset the BIOS to defaults, failed. I updated the firmware, failed. I came across a post, not necessarily related to Hyper-v core, but to Windows 2008 64 bit setup issues here. The suggestion was to blow away the current RAID set and recreate the logical volume. After blowing out the current volume and recreating, setup was able to complete successfully. The box I was on did indeed have a variety of previous operating systems, such as XenServer and ESXi. Somehow, even though I had “deleted” and formatted the partition on the Windows 2008 setup, there was enough information left over from previous systems to interfere with the proper loading of Hyper-v Core. Very odd…..