While running an upgrade Pre-Check against Hosts, a number of errors are returned for hosts that are no longer managed by NSX.
Errors may include:
- "Failed to execute Manager connectivity check."
- "Unable to retrieve Firewall module status on ESXi host"
- "Error while checking if host reboot is pending from a previous action."
- "Failed to execute ESXi maintenance-mode upgrade dataplane check."
- "Failed to execute ESXi supported versions check."
- "Failed to execute Maintenance-mode check."
- "Error while checking free space on ## partition on host"
- "Failed to execute DRS status check."
- "Failed to execute Maintenance-mode check."
- "Error while checking free space root partition on host"
- "Error while checking free space on tmp partition on host"
The name and UUIDs of affected transport nodes can be found in the pre-check error messages.

You may be able to verify some of these errors by using the API and retrieving the transport node state.
GET API '/api/v1/transport-nodes/{transport-node-uuid}/state' may show any of the following identifiers:
"node_deployment_state": {
"state": in_progress"
...
},
"deployment_progress_state": {
"current_step_title": "Removing host status"
...
},
"state": "orphaned",
...
"failure_message": "Host configuration failed. Number of retries: ###. Next retry attempt will be ..."
Searching for the {transport-node-uuid} may return a result, but following the transport node name hyperlink returns a filtered Hosts page with no results.
Example of following the hyperlink for the host: