Troubleshooting Tip: Unable to delete the FortiGate's central-management section
Description
This article describes how to recover the FortiGate from not being able to delete the central-management setting because of a GUI message:
'Please unregister device from FortiManager first' (GUI).
'Please unregister-device from FortiManager first. object set operator error, -582 discard the setting Command fail. Return code -582' (CLI).

Scope
FortiGate.
Solution
Investigate this problem. In the meantime, as a workaround:
- From the GUI, add 0.0.0.0 as the FortiManager IP.
- It will be logged out of the FortiGate.
- Log in again.
- It will be possible to set central management to 'None' without registering.
- Apply the changes.
If that does not work, run the following command on FortiGate CLI:
config system central-management
unset serial-number
end
config system central-management
set type none
end
Additional note:
For FortiManager Cloud, doing the change mentioned will still result in an error:
'Please unregister-device from FortiManager first. object set operator error, -582 discard the setting. Command fail. Return code -582'
In this case, unset the serial number of the FortiManager from the FortiGate:
config system central-management
unset serial-number
end