What is the first step to prevent some users from accessing a subfolder?

To effectively prevent some users from accessing a subfolder, the first step is to disable folder sharing. By disabling sharing, you ensure that the folder is no longer accessible over the network to unauthorized users. This control is critical in a scenario where data needs to be protected from certain users or groups. When folder sharing is disabled, no network users can access the folder, regardless of their permissions on the parent directory.

While hiding the folder may obscure its presence, it does not provide security, as users with the right access could still navigate to it if they know its location. Changing the owner could alter permissions but does not directly prevent users from accessing the folder unless accompanied by further permission changes. Blocking inheritance refers to preventing a subfolder from inheriting permissions from its parent, which can further restrict access but may not be the first action to take when aiming to secure a subfolder against specific users. Disabling sharing provides a definitive first step toward securing sensitive data from unwanted access.