Download the most recent version of the VirtualBox programming station of the TNC 640 from the download area in order to ensure that the installation file is up to date.
Open the downloaded .zip file with a right-click.
Navigate to the “Properties” context menu → “General” tab → Security (The file originates from a different computer. Access might be denied due to safety reasons.) → Click the “Unblock” checkbox.
Unpack the .zip file, and then install the programming station. It is important that you have administrator permissions on the installation PC.