When starting the LANCOM Advanced VPN Client for macOS X following an update to the operating system, the error message “Open logfile failed” sometimes occurs because the write permissions for the log file are missing or the folder NCP no longer exists.

This document describes the steps to take to prevent the error message Open logfile failed from occurring.


1) In macOS X, click on the Finder.

2) In the Finder, switch to the menu Go → Computer.

3) Double-click on the hard disk where the Advanced VPN Client is installed.

4) Check the path Library/Logs to see if the folder NCP exists.

5) If the folder NCP does not exist, create this in the Finder by clicking on File → New folder.

6) Select the folder NCP and, in the Finder, click on File → Get Info to view the permissions.

You may have to click the triangle next to Sharing & Permissions to view the permissions.

7) Click on Privileges and, from the drop-down menu, select Read & Write so that the write permissions are enabled.