In some situations (hardware failures etc.) it’s not possible to remove the Hyper-v cluster node nicely out of SCVMM. When removing the Hyper-v node from VMM it will throw an Error (25333) in SCVMM. This is because the server is down and it’s not possible to remove the SCVMM Host agent.
To solve this you can use the following PowerShell command:
remove-vmhost hostname –force