Restrict sftp user to a single directory in El Capitan
You need to make sure that the &lt;the directory path&gt; fulfils the next requirement specified in the manual pages for sshd_config(8):


  All components of the pathname must be root-owned directories that are not writable by any other user or group.


If you don't, then


  it doesn't work.


But you are certainly notified about the problem in system log.