If you are trying to update a client’s company client sector in the Client details page and the client does not have a company number you will get a message saying “Company Number cannot be empty.”
This will prevent you saving the client details without a mandatory company number field.
The Company Number is a mandatory field for the back office.
Alternative solution for this is to use the client bulk update tool within the clients list page.
See: https://hub.centricflow.co.uk/knowledge-base/clients/how-to-update-client-sectors-in-bulk-video/