0x8004230F translates to the VSS error “VSS_E_UNEXPECTED_PROVIDER_ERROR”, which generally means that the backup process could not initialize due to a third party VSS Provider component installed on the system. You can verify this by opening an elevated CMD prompt and typing VSSADMIN LIST PROVIDERS on the guest which is failing to backup.
VSSADMIN LIST PROVIDERS
If more than the default software provider is installed, another third party software suite may have enabled its provider on the guest. When this provider remains on the system when backup has ceased, it may cause problems for native backup and other tasks that attempt to initiate a VSS backup. This component of the third party software will need to be removed if Veeam Backup & Replication is to process this source guest consistently.
For more information on removing specific providers, please refer to vendor documentation regarding VSS Provider and Agent installation. In some instances, the VSS Provider component can be removed while keeping the rest of the software functionally intact.
It is critical that the following services must have their "Startup Type" set to "Manual"
The installed VSS Providers can be found in the following Registry Key: HKLM\SYSTEM\CurrentControlSet\Services\VSS\Providers\
It is highly advisable to export any key prior to removing it from the registry.
If the above troubleshooting steps does not resolve this issue, please review the solution on the this article http://www.veeam.com/kb1846.
The issue described in this article has been observed when a Hyper-V VM was converted or restored to a VMware environment. Afterward the now VMware VM retained its "Hyper-V IC Software Shadow Copy Provider", the presence of this Provider was determined to be the cause of the VSS_E_UNEXPECTED_PROVIDER_ERROR error. The backup admin was able to remove the Hyper-V IC Software Shadow Copy Provider provider manually and the error no longer occured.
The following is a non-exhaustive list of VSS providers which Veeam customers have reported had to be removed to resolve the issue described in this article: