A. This isn't an absolute rule, but system restore can lead to a significant amount of disk usage that will cause your dynamic disks to grow. I would recommend you disable System Restore for most VMs that are using dynamic hard disks. You can disable it on each VM, or for Windows 7 and Windows Server 2008 R2, you can use Group Policy. Go to Computer Configuration, Policies, Administrative Templates, System, System Restore, Turn off System Restore.
Ideally, you can apply this policy to a specific Organizational Unit that contains the VMs. Make sure you don't apply this Group Policy to machines that should still have System Restore protection.
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