Unattended access with NoMachine enables secure remote access to devices without requiring physical approval. It supports scenarios like remote IT assistance, accessing office computers, or managing unattended servers/IoT devices.  

How remote access to the desktop works
When you connect remotely to any desktop using NoMachine, system account credentials must always be provided in order to get access to that desktop. If you are connecting as the system's desktop owner, you will be taken to the desktop automatically after providing correct credentials.

When the connecting user logs in with a different system account to that of the owner, or is a guest (see Guest Desktop Sharing), the owner is requested to authorize the incoming request. Connection requests need to be manually accepted or rejected using the NoMachine notification pop-up which appears. This is an out-of-the box default setting which can be changed if required in the target computer's Server Settings. Access to the NoMachine desktop is managed in the Server Settings > Security panel. There are multiple options to fit a number of different scenarios depending on your needs and depending on the product you are using. A full guide to the Server Settings which fully documents all the various configurations is available here: https://kb.nomachine.com/DT05U00288#3.5.

Configuring unattended access
If you want to manage and control your remote machines even when no one is physically present at the remote end, or allow users to connect without requiring acceptance, there are three possibilities:

i) Connect as the owner of the desktop. Authorization is not requested when the incoming user and the desktop owner are the same account. This is a default configuration and suits users who are accessing and managing their own personal machine.

ii) Enable the "Don't require acceptance if the user logged in as system user" option in the above-mentioned Security panel. Ticking the box will allow users with valid system credentials on the host to connect without the need for the desktop owner's approval. This configuration is suitable for shared unattended computers and headless machines.

iii) The third way applies only to Cloud Server set-ups where Visitor Desktop Sharing is enabled and is available from version 9. By enabling the option "Don't require the visitor user to be accepted to be able to connect" in the node configuration of a Cloud Server users connecting in Visitor mode will not need the desktop owner's approval.