You can disable access to your physical desktop in just one click without stopping existing connections by toggling "Accepting connection is disabled/enabled" in the NoMachine monitor.
- Click on the !M icon (the "Monitor") in your system tray.
- Click on ‘Accepting connection is enabled’ to disable access to your desktop. The !M Monitor icon will be greyed out and no further connections will be allowed to the desktop.
To re-enable connections to the local desktop:
- Click on the greyed out !M icon and click on ‘Accepting connection is disabled’
For images check out the tutorial here: https://www.nomachine.com/disabling-access-to-your-local-desktop
Note that if you have installed a product which supports virtual Linux desktops (e.g Workstation) users will still be able to run virtual desktop sessions on the NoMachine server host even though "Accepting connections" is disabled.
TIP: if you want to prevent all users and all connections, select 'Stop the server' in the GUI. This will switch off server access. Further reading: https://www.nomachine.com/AR07M00852.