Microsoft have just released an updated offline VM servicing tool, which allows you to keep virtual machines that may be offline for a while, up to date with patches and the like.
Offline machines (which there are many of typically) do not automatically receive operating system, antivirus, or application updates that would keep them compliant with current IT policy. An out-of-date virtual machine may pose a risk to the IT environment. If deployed and started, the out-of-date virtual machine might be vulnerable to attack or could be capable of attacking other network resources.

You will need System Center (SCVMM) for this to work, which is understandable as this is a management operation.
You also need some mechanism for actually patching/updating the virtual machines. This is handled by one of the following:
- Windows Server Update Services (WSUS) 3.0 or WSUS 3.0 SP1
- System Center Configuration Manager
OVMST uses “servicing jobs” to manage the update operations based on lists of existing virtual machines stored in VMM. Using Windows Workflow Foundation technology, a servicing job runs snippets of Windows PowerShell scripts (against SCVMM, which is built on PowerShell) to work with virtual machines. For each virtual machine, the servicing job:
- “Wakes” the virtual machine (deploys it to a host and starts it).
- Triggers the appropriate software update cycle (Configuration Manager or WSUS).
- Shuts down the updated virtual machine and returns it to the library.
Its a good solution to solve the offline issue of virtualisation – try it, you can download it from here:

