A server with a robot was decommissioned and yet the robot still shows up in the Console.
Typically if the robot is deleted from the within the Console it will no longer show up but it is possible for it to fail in updating the robot.sds file resulting in the robot still showing up.
To resolve delete or remove C:\Program Files (x86)\Nimsoft\hub\robot.sds
Then restart the hub (in the IM console select the hub in the tree > right click Restart).
The robots.sds will be automatically recreated without any robots and as they connect back to the hub they get added.
This is copy of my knowledge document