Hyper-V Program Manager
We recently released KB956697 for Hyper-V.
This hotfix addresses a specific issue that we have identified with VSS support under Hyper-V. The issue is that if you have any invalid / corrupt / missing virtual machine configuration files - VSS will silently fail to backup *any* of the virtual machines on your system.
With this hotfix installed and virtual machines with invalid / corrupt / missing virtual machine configuration files will still not be backed up - but any valid virtual machines on the system will be correctly backed up.
There are two scenarios where you might hit this problem: