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
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:
- Go to Control panel -> Programs and features
- Find the SQL server in the list, select it and click Uninstall/Change:
- Click Repair in the window that appears:
- 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