Unitrends VSS snapshot issues due to multiple VSS providers

SUMMARY

VSS snapshot failures due to multiple VSS providers

ISSUE

VSS errors are common when investigating the failure of a backup/restore process.  Errors which arise due to an additional VSS provider being present will often be indicated by one or more of the following errors:

System shows errors such as:

(VSS_E_SNAPSHOT_SET_IN_PROGRESS) Another shadow copy creation is already in progress. Please wait a few moments and try again.
Please check Windows Events Log that Volume Shadow Copy Service and VSS Writers are operating properly.USnapCreate: USNAPError! Could not create snapshot, error -1.
: Unitrends agent was not able to create Volume Shadow Copy.
: To resolve this issue review the Event logs for any potential VSS errors and application specific Writer failures.

RESOLUTION

To accomplish this, the following steps may be used:

1. Using the first character string of the Provider Id (i.e. f5dbcc43 from the above example), perform a search in Windows Registry (regedit.exe) for keys showing the full ID string.
2. Delete each of those keys as they are discovered.
3. Close registry, reboot if desired

Once the key deletions are complete, re-run vssadmin list providers.  Microsoft Software Shadow Copy Provider should be the only provider showing.  This will then allow the Unitrends system to perform backups and restores without complication from an additional VSS provider.

Third-Party Sources

http://social.technet.microsoft.com/Forums/en-US/winservergen/thread/ee8d3dd2-99be-4eaf-80e7-7d2819a0c4fa

CAUSE

When initiating a check of the Windows Event Viewer Logs, further evidence may be demonstrated by the following:

Event Type:     Error
Event Source:     VSS
Event Category:     None
Event ID:     1
Date:          9/12/2012
Time:          1:56:29 PM
User:          N/A
Computer:     SQL-SERVER
Description:
Volume Shadow Copy Service initialization error: the control dispatcher cannot be started [0x80070427].

Event Type:     Error
Event Source:     VSS
Event Category:     None
Event ID:     12292
Date:          9/14/2012
Time:          12:42:45 PM
User:          N/A
Computer:     SQL-SERVER
Description:
Volume Shadow Copy Service error: Error creating the Shadow Copy Provider COM class with CLSID {5fc845eb-f299-40f0-9725-34045f7ea8ba} [0x80040154].

Event Type:     Error
Event Source:     VSS
Event Category:     None
Event ID:     20
Date:          9/14/2012
Time:          12:42:45 PM
User:          N/A
Computer:     SQL-SERVER
Description:
Volume Shadow Copy Service error: A critical component required by the Volume Shadow Copy service is not registered.  This might happened if an error occurred during Windows setup or during installation of a Shadow Copy provider.  The error returned from CoCreateInstance on class with CLSID {5fc845eb-f299-40f0-9725-34045f7ea8ba} and Name HWPRV is [0x80040154].

This particular combination of errors from the appliance logs and from the Windows System Event Viewer Logs support the fact that an additional VSS provider may be present on the system in question.  This can be further substantiated by checking the Windows system by using vssadmin list providers.  

C:\>vssadmin list providers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001 Microsoft Corp.

Provider name: 'Microsoft Software Shadow Copy provider 1.0'
   Provider type: System
   Provider Id: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Version: 1.0.0.7

Provider name: 'Acronis VSS HW Provider'
   Provider type: Hardware
   Provider Id: {f5dbcc43-b847-494e-8083-f030501da611}
   Version: 1.0

This indicates that at one time or another, the system had an Acronis product installed.  Even though the product may have been removed, some of Acronis' registry keys are known to linger on systems indefinitely.  The keys MUST be removed in order to remove the additional provider from the system.  Other backup vendors may have their own provider including Datto and StorageCraft.