Comment 1 for bug 1428698

Your device is reporting no available storage. Usually, this kind of error can be fixed
by rebooting both the device and the computer. If that does not work, you can try resetting
the device, or you can use one of the wireless communication methods described here:
http://manual.calibre-ebook.com/faq.html#how-do-i-use-calibre-with-my-android-phone-tablet-or-kindle-fire-hd

 status invalid