One of abilities that I thought Microsoft had removed from the new or ‘modern’ SharePoint interface was the ability to open a document library using the Windows Explorer file manager. Turns out that feature is still available as you can see from the above image.
You’ll find View in File Explorer option in the top right of a Document Library under the All Documents option. However, as with the previous Open in Explorer option, it is only available if you are using Internet Explorer. The reason it doesn’t appear in other browsers is because it uses an Active X control.
When you select the option a new tab will open in a browser and you’ll see the ‘classic’ interface.
A few moments later the Document Library will open in Windows Explorer as you can see above. You can now drag and drop files directly into the library using Windows Explorer as you could previously.
So the ‘trick’ to opening a Document Library with Windows Explorer using the new SharePoint interface is to once again use Internet Explorer and then select View in File Explorer from the All Documents option in the top right of the library.