Vista - Server 2008 backup fails with VM running

I have a problem with full Windows Server 2008 Backup since I installing
Virtual Server and creating a Windows Server 2003 R2 virtual machine. If the
virtual machine is turned off the backup works fine, otherwise it fails with
these errors...

Virtual Server...
The VSS writer for Virtual Server failed during the PostBackup phase, during
the mounting of disk
\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy76\Users\Public\Documents\Shared
Virtual Machines\Win2k3VPC\Win2k3VPC.vhd for virtual machine Win2k3VPC. The
disk did not come online within 5 minutes. Confirm that the vhd mount driver
in installed correctly and is able to mount virtual hard disks.

Backup...
Backup started at '{bc533fe1-2597-4311-9270-733cf0496240}' failed as Volume
Shadow copy operation failed for backup volumes with following error code
'2155348001'.

The host physical machine is a HP Compaq dc7800 with 4GB RAM and a 720 GB
Seagate Barracuda SATA hard drive running Windows Server 2008 version
6.0.6001. The O/S is configured as a workstation (Vista themes etc). The
virtual machine is a 10GB VHD running Windows Server 2003 R2 SP2 version
6.0.6001.The only software the VM is running is SQL Server 2000 SP4
(developer Edition).

Virtual Server versions are ...
Host:
Virtual Server version 1.1.629.0 EE R2 SP1
Administration Website version 1.1.629.0 EE R2 SP1
Support drivers Virtual Machine Monitor (Version 1.1.629.0)
Virtual Machine Network Services Driver (Version 2.6.623.0)

Machine Additions: 13.820

In case anyone wnats to know: Changing the disk type from Basic to Dynamic on
the guest OS fixed the problem.

"HMike" wrote: