VSS asynchronous operation is not completed. Operation: [Gather metadata]. Code: [0x80042318].
When running the command "VSSADMIN LIST WRITERS" nothing is displayed in the list on the affected guest. The behavior is consistent even after a reboot, applying Volume Shadow Copy Service (VSS) update package for Windows Server 2003, manually starting the VSS Service, and manually re-registering the VSS Components. The server was capable of performing VSS enabled backups in the past.
The COM+ subscription information for VSS writers stored in the registry under HKLM\Software\Microsoft\EventSystem\{26c409cc-ae86-11d1-b616-00805fc79216}\Subscriptions key may become corrupted.
Please follow the steps outlined in the knowledge base below to resolve the issue.
http://support.microsoft.com/kb/940184/en-us