I’ve seen quite a few posts about this problem lately - both in public, and on internal Microsoft mailing lists - so I thought it might be best to write up a quick blog about it.

This is one of those cool little problems that you can debug with almost no information, so you’ll look like a genius (or a witch, I suppose…) when you come up with the solution.

So, here’s the problem:  A user tries to boot up a Win7 or Win2k8R2 VHD (or even sometimes a Win2k8 VHD) in Hyper-V, the VM just sits there at the boot up screen forever, refusing to boot to the desktop. 

Now, that may not sound like a lot of information – and it’s not – but that’s almost everything you need to diagnose and fix the issue.  There’s one more piece of information that you’ll need, and luckily, you’ll usually get it.  Almost every time I’ve seen someone ask a question about this issue, they have included a screenshot of VMConnect showing the VM doing nothing.

You might laugh at that – I mean, it’s not often that a screenshot of “nothing happening” will give you all of the information you need to solve a problem, right?  In this case, though, it does.

Here’s a sample screenshot that I took:

image

 

It’s too small to see at this size, so I’ll zoom in on the important part – the upper-left corner:

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See it yet?  If not, channel Dr. House and think about what you’re seeing…  Those icons look kind of… unfinished – don’t they?

Good catch.  Those are the icons from the beta release of Hyper-V, which means that the parent partition was never upgraded to RTM.

Here are the icons from the RTM and R2 release:

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The fix?

Update the parent partition with KB950050, or with SP2.  Keep in mind, though, that you’ll need to re-create all of your VM configurations (you can keep the VHDs around – just attach them to the new VM) after you apply the update, and you’ll lose any save-states or snapshots.