Q. How do I register the Hyper-V VSS writer with the built-in Windows Server Backup application?

A. I'm a big Microsoft fan, but it's a pretty well known fact that sometimes the corporation makes decisions that don't make sense.

Hyper-V provides a great VSS writer that lets VSS snapshot requests be forwarded to guest OSs so that the integrity of virtual machine (VM) backups is ensured as the VSS writers in the guest OSs are activated.

Windows Server has a backup application, Windows Server Backup. Many companies may use the in-box backup application to back up their Hyper-V servers, thinking the great Hyper-V VSS writer is being used. Well, it's not. By default, the VSS writer for Hyper-V isn't registered with Windows Server Backup, which means the backups you make with the in-box tool aren't calling the VSS writers in your VMs. The backups you make of your virtual hard disks may not actually be usable in a restore situation.

The solution is to register the VSS writer with Windows Server Backup manually.

Alternatively, save the following into a file named hypervvsswriterregister.reg then double-click it.

Windows Registry Editor Version 5.00[HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWindowsServerBackupApplication Support\{66841CD4-6DED-4F4B-8F17-FD23F8DDC3DE}]"Application Identifier"="Hyper-V"

This will create the keys and values for you.

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