The best way to prevent future occurrences of active network accounts belonging to former employees is to conduct a comprehensive review of access management processes. This review should include verifying that the access rights of all employees are updated regularly, especially when they change roles or leave the organization. The review should also ensure that there are clear policies and procedures for granting, modifying, and revoking access rights, and that these are followed consistently and documented properly. The review should also identify and address any gaps or weaknesses in the access management processes that could lead to unauthorized orinappropriate access. By conducting a comprehensive review of access management processes, the organization can improve its security posture and reduce the risk of data breaches or misuse of resources. References = IT audit: The ultimate guide [with checklist] | Zapier, IT auditing and controls - planning the IT audit [updated 2021]