When attempting a queisced backup of a VM it fails with
"The guest OS has reported an error during quiescing.The error code was: 5 The error message was: Asynchronous operation failed: VssSyncStart "
The new Vmware tools - VSS & VZshadow tools in ESXi 5.0 on 2008 and 2008 R2 machines
Note: This requires a reboot of the virtual machine. VMware recommends scheduling downtime before performing this action.