"Failed to update VM properties", "host already exists" general errors after Upgrade/Restore of vCenter or deploying a new vCenter - unable to update

SUMMARY

When you upgrade, replace, or deploy a new vCenter or modify it in such a way that the UUID or Instance ID changes and the changed information is not transmitted to Unitrends, a disassociation occurs.

ISSUE

When you upgrade or deploy a new vCenter or modify it in such a way that the UUID or Instance ID changes, Unitrends is no longer can communicate with vCenter. Any action that requires an updated to the tables that validate ESXi hosts, vCenter, or Guest VMs will generate an error concerning communication or update failure such as:

• Failed to update VM properties.
• Cannot add ESXi hosts after adding vCenter... host already exist. and Unable to upgrade issues​.
• May be missing VMs or Jobs fail indicating the VM could not be reached.

RESOLUTION

If you are using the Legacy /recoveryconsole/ Administrative Interface, please make the following notes:

• Protected Assets  = Settings > Clients, Networks, and Notifications > Clients
• Replication = Jobs > Backup Copy (this is considered a Hot copy, because deduplication continues).
• Archives = Jobs > Backup Copy (this is considered a Cold copy, as the data is rehydrated <un-deduplicated>)
• Inventory Sync = Select the vCenter in the Navigation Pane, then click on Backups (big icon on the top). On the bottom of the Schedule pane under the list of VMs, you will see two arrows in a circle. Click this icon. Once completed, do the same for the under the Navigation pane. Again refresh the Schedules VMs.
• Backup Copy Target (adding NAS) = Storage > Storage and Retention > Storage > Add Archive Storage

1. Ensure your  Unitrends appliance is on the current release to ensure proper operations and supportability.
2. Add all ESXi hosts related to any Guest VMs you are protecting using the CONFIGURE > Protected Asset (tab) on the Unitrends. You must select Virtual Hosts > VMware as the Hypervisor Type, and use the username of root and the password for that root user on the ESXi hosts.
3. Edit the Protected Asset for vCenter and re-enter the password, then save.
4. Perform an Inventory Sync to load the updated data from the vCenter: Click the Options icon  on top right of the page and select "Inventory Sync"

1. In the event of data loss, we strongly recommend that you have a recent Cold Backup Copy. If you do not have this in place, you can add a NAS as Backup Copy Target and create a Backup Copy Job, select the newly added NAS and choose the Now option for the schedule. This will run once, creating a copy of the data for the VMs you selected.
2. If you are currently Replicating the virtual backups, you are covered. However, the step above does give you localized protection and faster restores.
3. Delete the vCenter from the Protected Assets page. (You MUST delete the Backup schedules as well as uncheck the vCenter/VMs from the Archive schedule.
4. Add vCenter back to the Client page. Create the schedules.
5. Verify everything is working as expected.

1. Add all ESXi hosts that are related to the Guest VMs that you wish to protect, to the Protected Assets or Clients Page. Once added, you will see the VMs that are associated to each ESXi (in the Legacy Interface, you must click in the gears icon at the bottom of the Navigation pane, and choose to show the Virtual Machines)
2. Add the vCenter server.