Which of the following is NOT a common CAC issue?

The correct answer, that outdated network drivers are not a common CAC issue, can be understood through the nature and function of the Common Access Card (CAC) system. CAC primarily deals with user authentication and access control, specifically providing secure access to various systems and services.

Issues like smart card service not working typically arise from problems with the CAC itself, the card reader, or the software responsible for communicating with the smart card. Incorrect user permissions often relate to how a user's access is managed through their CAC, determining what resources they can access based on their role, which is vital in a tightly controlled environment like military or government systems.

GOW, or Get Out of the Way, for encrypted email represents a specific function Fortified by CAC usage, as encrypted email systems require successful authentication via the CAC to ensure that sensitive information is only accessible to authorized personnel.

Outdated network drivers, while they can lead to network connectivity issues, are not specifically tied to the functioning of a CAC. The CAC itself deals more directly with authentication protocols and access rather than underlying network infrastructure. Thus, while keeping network drivers up to date is important for overall system performance, it is not categorized under common CAC problems.