High Density Configuration / HD Configuration Step by Step guide

To setup multiple user logins and execute robot in Unattended mode you need to implement all the guideline the below link:

In addition to the above you need to make few changes on the Individual Robot machine in case if you run into Error : A specified logon session does not exist 0x80070520

Error Description

Executor start process failed, reason System.Runtime.InteropServices.COMException (0x80070520): A specified logon session does not exist. It may already have been terminated. (Exception from HRESULT: 0x80070520)

Solution For the above Error :

Please follow the below 4 guideline and make the changes.

a) Config RDP timeout to create user session
If UIPATH_SESSION_TIMEOUT is not defined , define the value and set it to 120.

b) Verify if the Robot user and the everyone is added to the below policies. In case not please add it. (Screenshot for reference)
-Access this computer from the network
-Allow log on locally
-Allow log on through Remote Desktop Services.
-Log on as a batch job


c) Navigate to system properties and verify if the below options are selected for the system


d) %programdata% / UiPath / UiPath.Settings file changes

  • Verify the value of logintoconsole if set to β€œfalse” ? This is essential when you are executing process in unattended mode.
  • Also make sure the proper resolution setting has been defined i.e. height, width & depth.

The below snapshot shows the configuration done in my machine for the Robot to execute in unattended mode with a specific resolution. The resolution is taken from the dev environment where workflow was developed and applied on the Robot machine in UAT/ PROD environment.

Robot machine:

  1. Login to the robot machine.
  2. Open uipath folder under program data. Add in UIPath.settings file the height depth and width that you have noted in the appropriate parameters. Logintoconsole: false (small f)
  3. Restart uipath robot services (Run -> services.msc -> Uipath Robot -> Restart)
  4. Reboot the machine.
  5. Logoff from the system.

Note : Every single steps is equally important. After setting up all the configuration , you can leverage the functionality of HD.