When switched to Dark Mode in Windows 10 , the File Explorer shows a horizontal white bar under the toolbar:
- Open Internet Explorer.
(If you can’t find Internet Explorer in Windows 10 , you can press
Win+Sto open Search, then search for Internet Explorer and click the result to open it.)
Right click on any free area of the toolbar on the top of Internet Explorer, make sure Lock the toolbars is checked.
Close all folders, open the File Explorer again, now the white bar is gone.