Beware Anti-Virus and Hyper-V

I released the July updates onto our network this past weekend.  I’d also deployed our new AV the previous week.  Let’s just say that AV mixed with Hyper-V and followed by a reboot made for a nice mess.

I logged into the Hyper-V lab this morning to find half of my VM’s were missing.  They’re sitting find (but idle) on the storage.  It’s just Hyper-V has "forgotten" that they ever existed.

I trawled through the Windows Event logs (Application and Service logs – Microsoft – Windows – Hyper-V-Config – Admin) and found a series of these:

Source: Hyper-V-Config

Event ID: 4096

Level: Error

The Virtual Machines configuration <big long GUID> at <path to VM> is no longer accessible: The requested operation cannot be performed on a file with a user-mapped section open. (0x800704C8)

Ok.  A bit of googling found an entry on the TechNet forums that says you need to disable scanning for the VHD’s and the XML files of your VM’s.  Ouch!

OK, so I did that and rebooted by lab server.  Still no dice.  Actually, Hyper-V doesn’t even bother attempting to load these VM’s now.  OK, I’ll do what I would in any other virtualisation product; I’ll open them.  Ick … no open command.  Import?  Nope; because MS in their wisdom (!) decided that the import/export format should be different to that of a normal VM. 

So I’ve got a plethora of VM’s that are sitting on my disk in a saved state that I cannot load up.  My only way forward is to re-add the virtual hard disks as new VM’s.  This is a pain:

• I lose my saved states.
• I have to reconfigure every single VM that is missing.
• Each VM has to do the PNP dance with a "new" NIC and I have to reconfigure IPv4 addressing.
• It’s just lots of work I shouldn’t have to do.

I’ve logged a bug report with MS.  I’m open to any constructive suggestions.