Sometimes Windows insists on not wanting to properly eject USB sticks and disks, you can use ProEject for this purpose! Lightweight and easy to use: in one click you can eject all USB devices.
For a user guide: fribby.net/proeject/?lang=en.
Official program page: softwarespot.wordpress.com/software/proeject/.
Free Download ProEject:
File
License terms
ProEject is released under GPLv3