1) Connect USB to Mac and open it.
2) Go to search box on top right and press space bar once.
3) By default search will be highlighted at search>this mac, click on the USB name beside that.
4) Press + sign at right hand side beside save option
5) From the dropdown which says ‘any’ choose ‘folder’ and you will see all the folder present in the USB. Copy and save it.
Hope this helps!!!!!