Hello guys,
Yous can copy with another application : "Calibre", freeware.
To do that:
Access to your "Kindle's" ebook library, you can change folder in "Settings" of Kindle app.
Then right click on the ".azw" files and "open with", "Calibre".
After few seconds of importation in "Calibre" just double-click on ebook, and voila.