This problem usually happens when WebHarvy is run with multiple monitors attached to your computer/laptop and later you have disconnected the extra monitor. Please try any of the solutions given below :
Solution 1:
Hover mouse over WebHarvy application icon (in taskbar) so that you can see small preview of the Miner window. Click on the Miner window so that it becomes the active window.1. Now hit ALT + Space Bar
2. Press the 'M' key
3. Now you can use the up/down/left/right arrows in your keyboard to move this window around so that you might get it back in the current desktop. Once you start using the arrow keys, you can also use the mouse to move the window around.