I attached a Toshiba 3tb usb 3.0 drive to MyCloud. I selected 20ea files (Movies) from a folder from USB drive to transfer using MyCloud Desktop MyCloud hanged up after a few minutes and the dashboard closed. The files was copied but when I checke the USB drive the whole folder was gone. I unpluged the drive and checked it on the computer and the folder was not there I lost about 23g of movies.
I had the same problem transfering some music files using the my cloud desktop app. I copied the folder and pasted it in another and then the app froze up. Luckily i had another copy of the file but that was 40GB of music.