To provide access to a newly created content library that users cannot see, what should an administrator do?

In order to grant users access to a newly created content library that they currently cannot see, establishing a security rule is the most appropriate course of action. Security rules in Qlik Sense serve as the governing mechanism for controlling access to various resources, including content libraries. By creating a specific security rule, an administrator can explicitly define who has access to the content library, effectively managing visibility and permissions according to the organization's needs and policies.

This method enables the administrator to customize access levels based on user roles, ensuring that only designated individuals or groups can view or interact with the content library. Unlike setting permissions for individual users, which can be cumbersome and lead to management challenges as the number of users grows, utilizing a security rule allows for a more scalable and organized approach to access control.

The other choices provide less efficient solutions. For instance, notifying users to refresh their session does not address the visibility issue directly, as users would still lack the appropriate permissions to see the library. Recreating the content library is unnecessary if the sole requirement is to update access permissions. Additionally, while setting permissions for individual users might be applicable in very limited scenarios, it does not provide the systematic approach that security rules offer in managing access to content libraries.