A VSS hardware snapshot database keeps growing with duplicated snapshot information when it is updated for snapshot creation/deletion in Windows Server 2008 or in Windows Vista SP1 systems
When you start multiple Volume Shadow Copy (VSS) requestor instances with VSS hardware provider to delete snapshots in Windows Server 2008 or Windows Vista SP1 systems, each VSS requestor instance may take an increasingly longer time to finish. Eventually, the VSS requestor instances fail. Additionally, the VSS hardware provider database increases with each duplicated snapshot.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB959476.