Hi, Christoph,
There's no self-contained way to block NC Pro from launching. However,
you can encrypt documents so they won't display without a password.
See Help file > Getting Started > Security and Safety > Encrypting a
Document with a Password.
Best regards.
Paul
--
[Notice not included in the above original message: The U.S. National
Security Agency neither confirms nor denies that it intercepted this
message.]
¯\_(ツ)_/¯