Hello @Nikunjkumar Desai ,
This is Dhwanit Parekh from Automation Anywhere technical support team.
The error occurs because, while installing the bot agent, "Only for me" options is selected, which installs the bot agent application for local user only with non admin privileges.
Which such type of bot agent installation, only "bot creator" and "attended bot runner" devices are supported.
Follow below steps to resolve the error and to register the device as unattended bot runner.
1) Deregister the device from control room.
2) Uninstall bot agent and clean up respective folder.
3) Reinstall bot agent with "Anyone who uses this computer (all users)" option, which requires admin privileges.
4) Register the device again now.
Attempt your task now and you should be able to make it a default device for your user.
Hope this helps.