How to fix the “Cannot attach the virtual hard disk …

Little backround.
I use Acronis to create images for true disaster recovery ability. With Acronis I can also mount back up images and retrieve any needed files in minutes! The newer versions of Acronis also allow you to convert your Acronis images (.tib) into Microsoft Virtual Hard Drives (VHDs).
[Acronis has solutions for home and enterprise users and is worth every penny! Personal edition is under $50.00 and for corporations it is well worth the price for true peace of mind.]
So back to my VHD issue.
Virtual hard drives can be used to create full blown Virtual Machines (VM)and are ready to use with MS Virtual PC or MS Virtual Server. I am a long time VMWare user too, but I am working on getting much more profecient with MS’s solutions since they are my primary support calls
Another cool tool is the Microsoft Sysinternals Disk2vhd tool. This can create VHDs from any MS Windows version from XP forward.
I’ve been able to mount the VHDs created with this tool and been able to retrieve files with ease.
So after creating a few VHDs with the Disk2vhd tool I decided I wanted to use one of those VHDs to create a full blown VM and run it with Virtual PC on my Windows 7 laptop.
With Windows 7 and 2008 Server you can very easily ‘mount’ VHDs right from the Disk Management console. They can also be very easily converted to other image formats that can also be ‘mounted’ so you can retrieve your files.

However after trying to create the VM and ‘attach existing VHD’ I keept running into a very frustrating problems.
I kept getting this message “Cannot attach the virtual hard disk …”
What does it mean? Not much info in the error, arrrg.

It means you have a Virtual Hard Disk file larger than 127.5GB. Which Virtual PC does not support.
After lot’s of searching I found this article:
How to fix the “Cannot attach the virtual hard disk …” wisefaq.com

This very well presented article is great. It helped me to solve the problem fairly easily!
But I have something to add to this fix that make it so much easier!
You can simply ‘attach’ the drive in Windows 7 (Windows 2008 Server too) Computer Management Console>Disk Management, then right click and ‘shrink it’. Once that is done ‘un mount’ and then use VHD Resizer!
That’s it. Skipping the use of DiskPart. Very easy and quick.
Just thought I’d pass that on for any of you other techies who have run into that or may in the future.

7 Responses to “How to fix the “Cannot attach the virtual hard disk …”

  1. You have just saved me from a very-very-very frustrating 3 hours working with this. I can’t believe I finally found the answer on your site!

  2. Earnest Lutts on June 29th, 2010 at 6:51 am

    Thanks for this interesting information.

  3. Raleigh Larriva on June 29th, 2010 at 6:56 am

    This is a interesting post.

  4. Lashawna Alix on June 29th, 2010 at 1:47 pm

    I love your site.

  5. Book-marked your internet site. Appreciation for giving. Definitely worth the time for my personal research.

  6. Note that, using DiskManagment or DiskPart, you cannot attach your VHD from Disk2VHD while the the original disk is attached. You get a signature collision.

    You have to take the original disk offline, or go to a different computer, to attach the VHD.

  7. Nice Post mate.

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