We should have any on going connections with the VM like user logins. to avoid this we have to restart the VM to make sure that no user logged into this VM machine.
Have you installed the Bot which you are running as un attended from orchestrator by using MSI installer since we must install the bot with service mode since service mode bot is required for un attended automation.
Make sure that you assigned un attended bot license for the Bot(VM) which you are trying to run your process un attended.
please check above points and let us share your confirmation. thanks.
Make sure the robot installed is in service mode
This is very essential in order to let your bot run in unattended mode and also to access the UI elements
Finally Make sure the machine you developed and the machine where you are running this bot, has same resolution
If the resolution of those machine differs then UI automation will fail
Resolution can be set in ROBOT settings when you create your robot
Set the same height, width properties between the machines
If you are using only one machine then it’s completely fine with this point in specific