Registry change after installing Backup Exec 2010/2012 on a Hyper-V 2008R2 node

Installation of Symantec Backup Exec 2012 is fully supported on Windows 2008R2 Hyper-V nodes as described in the Software Compatibility List. However after rebooting the node, Hyper-V throws the following errors. Important to note is that the cluster itself is online without any warnings or errors as described in this post. The errors are visible after live migrating a virtual machine to the impacted target host or when you attempt to start a virtual machine on the impacted node.

‘VM Name’ failed to start.

Microsoft Emulated IDE Controller (Instance ID {########-####-####-####-############}): Failed to Power on with Error: ‘A device attached to the system is not functioning.’

Failed to open attachment ‘Drive Letter:\path\Virtual Hard drivers\VMNAME_########-####-####-####-############.vhd’. Error: ‘A device attached to the system is not functioning’

Failed to open attachment ‘Drive Letter:\path\Virtual Hard drivers\VMNAME_########-####-####-####-############.vhd’. Error: ‘A device attached to the system is not functioning’

and

‘VM Name’’ Microsoft Emulated IDE Controller (Instance ID {########-####-####-####-############}): Failed to Power on with Error: ‘A device attached to the system is not functioning.’ (0x8007001F) (Virtual Machine ID: ########-####-####-####-############)

Some research resulted in the following conclusion:

  1. In the Kernel Mode the following components exist:
    • Fsdepends.sys: File System Dependency Manager Mini Filter Driver
    • Vhdmp.sys: VHD Miniport Driver
    • vdrvroot.sys: Virtual Drive Root Enumerator
  2. The VirtDisk.dll uses the above mentioned components for starting the VDS VHD API’s.
  3. And those are used for the Virtual Disk Service which is configured with a manual startup type…

.

About VHD..

However the Virtual Disk service (vds.exe) may not be able to function correctly when the components in one of the lower layers is not started correctly. The reason for this is that the startup priority is configured to be started after all other services are already started. This configuration can cause a third-party backup software to load and initialize it’s tape device drivers, etc.. not allowing fsdepends to be initialized in the appropriate manner.

To resolve this issue, you can implement the following workaround:
1) Start Registry Editor.
2) Visit the following registry key: “HKLM\SYSTEM\CurrentControlSet\Services\FsDepends”
3) Under the “FsDepends” key, change REG_DWORD value “Start” from “3” to “0”
4) Restart the computer

For more information, please consult:

As a best-practice, I would say to alter the registry information on each new installation with Hyper-V on it.

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