We had an issue last week where backups of an Exchange 2007 server began to fail after we removed the EMC Replication Manager & EMC Solutions Enabler apps. The errors that we began to see in the Application log like this:

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 {bd902507-4491-4001-acdd-a540a2cad34b} and Name HWPRV is [0x80040154].

I went through the process described here http://support.microsoft.com/kb/940032  to reregister all the VSS stuff, but it didn’t work. After digging into the VSS CLI, I was seeing the following returned from issuing a “vssadmin list providers” [more]

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: 'ERM VSS Provider'
   Provider type: Hardware
   Provider Id: {e929a027-cf8c-47bf-90a3-cd4241c7cace}
   Version: 1.0

It appeared as if the EMC VSS provider was not removed when I uninstalled the software. The online knowledgebase for EMC, said to fix it, re-install the apps, then start the VSS service, then uninstall the apps again suggesting that the provider would not have been removed if the service wasn’t running at the time the apps were uninstalled. I had a really hard time getting that stuff installed to start with so I didn’t want to start that again. I did some testing on a VM and found that I could remove the provider by just removing the registry key which matched the Provider Id listed by the vssadmin list providers command.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VSS\Providers\{e929a027-cf8c-47bf-90a3-cd4241c7cace}

After restarting the VSS service one time, the vssadmin list providers command provided this output

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

Success!! This could possibly be a problem and the fix could work with any applications that insert 3rd party VSS providers.