Symptoms

• You are backing up a Hyper-V virtual machine in agentless mode,
• Backup fails with the following error:

  Unexpected call result. Error code 32768

| error 0x53009a: Failed to process the call results.
| line: 0x6d1fe7f1e47ba1dc
| file: d:\258\enterprise\virtualware\raw\microsoft\hyperv\hv_job_utils.cpp:299
| function: VirtualWareRaw::CreateWmiJobStatusByCallResult
| $module: hv_srv_vsa64_29051
|
| error 0x5301c2: Unxpected call result, error code: '32768'
| line: 0x6d1fe7f1e47ba1d8
| file: d:\258\enterprise\virtualware\raw\microsoft\hyperv\hv_job_utils.cpp:295
| function: VirtualWareRaw::CreateWmiJobStatusByCallResult
| $module: hv_srv_vsa64_29051

Cause

The most frequent root cause are VSS issues in the guest operating system.

Troubleshooting 

If there is an SQL Server installed on the virtual machine:

Repair the SQL instance on the guest VM:

1. Go to Control panel -> Programs and features
2. Find the SQL server in the list, select it and click Uninstall/Change:

   

3. Click Repair in the window that appears:

   

4. After repair install completes, retry the backup.

If the issue is not resolved, troubleshoot snapshot issues on Hyper-V as described in Troubleshooting Hyper-V snapshot issues

If there is no SQL server on the virtual machine:

Troubleshoot VSS-related issues on the guest OS as described in KB 36200: VSS Troubleshooting Guide