The following will often fix the problem but probably not always. Go to Windows Explorer and select Tools>Folder Options>View> and check the "Launch folder windows in a separate process" check box.
Or
In the Control Panel, clicked on the Ease of Access Center
Under Explore all settings, clicked on Make the mouse easier to use
Under Make it easier to manage Windows, checked the box Prevent Windows from being automatically arranged when moved to the edge of screen
clicked on Apply, then OK