1. Open Displays settings from Ubuntu Start Menu.
|Open Displays Settings|
2. If you are lucky you will see two rectangles shape in the Displays window (red and green). Click on the green colored rectangle with "Unknown Display" on it, as seen below.
|Displays Settings "Unknown Display"|
3. As you can see in previous image, the Unknown Display is turned on. Click on the switch to turn it off. Then click on "Apply" button.
|Turned off Unknown display|
That's how I fixed my problem with the mouse cursor. If you find this tips helpful, please leave a comment below. Thank you :)