The problem seems to be that if you move the mouse over the search icon at exactly the right speed the search hover menu for the search icon crashes because you move off of the icon before it has finished it's animation and rendering.
The solution is:
- Right-click on the task bar
- Click on taskbar settings
- Turn off Search (it is redundant anyways - just click Start and start typing to open the search box)
If you have the problem at the time, restart Windows Explorer as described in other posts here (Ctrl+Shift+Esc , press w (to jump to the "W"s), right-click on Windows Explorer, click Restart)
BTW (for beginners): I am using "right-click" as shorthand for secondary click which may be 2-finger click, 2-finger tap, long touch (or left-click if using a left-handed mouse) depending on your device.