I encountered this one just a short while ago tonight. It’s been mentioned elsewhere before. I was doing some work on some VM’s and I used the Hyper-V MMC to upgrade the integration components and reboots. VMM 2008 did a refresh and suddenly the VM’s had the “unsupported cluster configuration” status. I got a brief warning about unclustered storage. The LUN’s being used for the VHD’s were fine. I did a quick search and the result made perfect sense. The integration components ISO was still mounted on the host. Moving the VM from one host to another would break that because the ISO is on the host, not on the LUN. VMM picked up on that. I unmounted the ISO and all was well again after a repair-ignore job.