Hyper-V Guests suddenly stopped working

Question

Here's my configuration: Windows Server 2008 R2 Standard as a host OS, and two guests VMs running the same exact OS.

Yesterday, Trial Activation on all OSes has expired and quite naturally all machines shut down. I rearmed the host, but cannot log on to either guest VMs. From what I see, they start up normally (State is listed as Running) but CPU Usage seems to be stuck at 3% and when I connect to it all I see is black textmode screen with cursor blinking.

One of my VMs has several snapshots, and when I revert back, it starts up normally. Moreover, "reference VM" (the one I cloned these two VMs from) starts up just normally.

How can I troubleshoot this issue?

Answer 1

this sounds like a corrupt image.

if you are saying an old snapshot starts up fine while the new one is giving the black curser, there is a chance that during the license expiry shutdown, some changes on the image disk took place preventing it from booting again.

Answer 2

Got it figured.

After Googling around, I found out that the most likely cause of this problem is MBR/Boot record fuckup. To solve this issue:

• Boot from Windows Server 2008 R2 ISO/Disk
• Click your way through "Restore" to "Command Line"

• Execute following commands:

  bootrec /fixmbr

  bootrec /fixboot

• Reboot