Error Code 91:161 The provider returned an unexpected error code. The job will go to pending and will be retried.

Hyper-V VSS backup of Virtual Machine on Cluster Shared Volumes (CSV) fail with error code 91:161

Symptoms

Log entries:

CVSSClientShadow::CreateShadow() - Failed to create shadow.
CHyperVVSSInfo::CreateVSSShadowLocally() - Failed to create VSS shadow. hr=[0x8004230f]
CHyperVVSSInfo::GetVMInfoErrFromVSS() - VSS Reported Error : VM_ERR_VSS_E_UNEXPECTED_PROVIDER_ERROR (The provider returned an unexpected error code. The job will go to pending state and will be retried.)
CHyperVVSSInfo::GetVMShadow() - No existing shadow for VM []
CheckVMInfoError() - VM [] The provider returned an unexpected error code. The job will go to pending state and will be retried

Causes

This error occurs when the default VSS Provider is not the Hyper-V CSV Provider. The VSS provider needs to use the Hyper-V CSV Provider.

Resolution

To back up the VM's residing on CSV's, you need to add the following Additional Setting  to ALL Hyper-V hosts with Virtual Server Agent installed

1. Open the Commcell Console.
2. In the CommCell Browser, expand Client Computers and right click on the Client\Proxy.
3. In the Client Properties Dialog select the Advanced button and click on the Additional Settings tab.
4. Click Add.
5. In the "Name" text box enter VSSProvider
6. For "Category" select VirtualServer.
7. For “Type” selectString
8. In the "Value" text box enter - 400a2ff4-5eb1-44b0-8a05-1fcac0bcf9ff

• Make sure this above value is copied exactly as is, also make sure there are no trailing spaces when you paste it into the Console.

Repeat for each Hyper-V host/proxy. Retry the backup.