The Nomachine client application proposes to update to the latest version in its default configuration. Versions 6.0 and higher do not work with our configuration, and so auto-updates should be rejected. The query for updated versions can be disabled as follows:
Start Nomachine client
Click on the "Settings" button in top right corner
This will open the settings dialog.
Click on the Updates tab on the right-hand side
This will open the update settings.
Uncheck the box next to "Automatically check for updates".
This might require admin privileges on your computer. If you do not have those privileges, check with your IT staff.