vCenter Server reports vSphere HA host states that indicate an error condition on the host. Such errors can prevent vSphere HA from fully protecting the virtual machines on the host and can impede vSphere HA's ability to restart virtual machines after a failure. Errors can occur when vSphere HA is being configured or unconfigured on a host or, more rarely, during normal operation. When this happens, you should determine how to resolve the error, so that vSphere HA is fully operational.