How can I limit a user so that they cannot access files outside of a certain directory?
The answer depends on what sort of access you have in mind. For shell access and remote execution, jailing a user is possible only through Windows file system permissions. On the other hand, if you are permitting the user only file transfer access (using SFTP and SCP), you can configure a limited-access virtual filesystem for the user by editing settings for their account or group in WinSSHD Settings. If editing account settings, disable ‘Use default SFS map’, then open SFS virtual filesystem mount points, and set the ‘Real root path’ setting for the default mount point (‘/’) to the directory you want them to access.