virus scanners become smarter and smarter and these days not everyone is excluding certain files or directories anymore.

but i must say that i still make virus scan exclusions, because my opinion is that avoiding problems is better than fix (heal) them. For hyper-v this is the same, maybe more important because you are relaying on the so called “parent partition”. It is best practice to keep this parent partition as clean and mean possible. so don’t install unnecessary services/applications and exclude important files and folders from the virus scanner.

so configure the real-time scanning component within your antivirus software to exclude the following directories and files:

  • Default virtual machine configuration directory (C:\ProgramData\Microsoft\Windows\Hyper-V)
  • Custom virtual machine configuration directories
  • Default virtual hard disk drive directory (C:\Users\Public\Documents\Hyper-V\Virtual Hard Disks)
  • Custom virtual hard disk drive directories
  • Snapshot directories
  • Vmms.exe
  • Vmwp.exe

Additionally, when you use Live Migration together with Cluster Shared Volumes on Windows Server 2008 R2, exclude the CSV path “C:\Clusterstorage” and all its subdirectories.

Notes

  • If virtual machines are missing from the Hyper-V Management console, you must configure the antivirus exclusions, and then restart the Hyper-V Virtual Machine Management service.
  • If you receive error code 0×800704C8, it is likely that the virtual machine configuration file was corrupted. In this case, and if restarting the Hyper-V Virtual Machine Management service does not resolve the issue, the virtual machine has to be re-created or restored from a backup.

more on this at http://support.microsoft.com/default.aspx/kb/961804