After upgrading vCenter Server from version 7.0 to 8.0, custom local OS users are no longer present on the appliance.
Local OS users are not visible in the vSphere Client.
Running the appliance shell command localaccounts.user.list does not display the previously existing local OS users.
VMware vCenter Server 8.0.x
The vCenter Server upgrade process does not migrate custom local OS users.
This is expected behavior, and there are no methods to migrate the custom local OS users during the upgrade.
You can manually recreate them on the upgraded appliance.