When an employee leaves, it is often a first step for the business that his personal access to their professional mailbox is cancelled as soon as possible (often even during the exit meeting). But most often that mailbox will remain open for quite some time after the termination, as there is a genuine business concern that e-mails may still come in after the termination that are of entirely legitimate interest to the company, such as in relation to orders or ongoing matters requiring to be picked up by someone else.
