Failed to start service ‘VeeamDeploySvc’ when adding Hyper-V host

Adding a Hyper-V server to Backup Infrastructure fails with the following error message:

This can be the result of a version mismatch between the .DLL and service on the Host. Check the versions of the files as shown below:



This will also manifest as the Veeam Installer Service refusing to start from services.msc. Note as below that the Veeam Data Mover Service starts, but the Installer Service is not running and cannot be started:

The goal is to manually resolve the version of, and cleanly remove, the deployed components. To do so:

1. Verify all of the above to identify this issue positively. If the version mismatch does not exist, you may wish to contact Support.
2. On the Veeam server itself, navigate to “C:\Program Files\Veeam\Backup and Replicaton\Backup\Packages” (if default installation path is used).
3. Copy VeeamDeploymentDll.dll and VeeamDeploymentSvc.exe to the target host in the path “C:\Windows\Veeam\Backup”. (You may need to grant permission to perform this copy.)
4. From an Administrator command prompt, run: sc delete veeamdeploysvc
5. Double-click on the service executable on the host, and choose “Repair” as you proceed through the wizard.

 
For details on the sc delete command, see https://technet.microsoft.com/en-us/library/cc742045(v=ws.11).aspx
 
You should be able to add the host now through the Veeam console at this point.