Comment 3 for bug 1347340

I am also seeing this problem with my tablet and have for quite a while.

calibre: 2.51
OS: Mac 10.11.3 (El Capitan)
Device: Samsung Galaxy Tab S - Android 5.0.2

I can access my tablet when plugged in using the Android File Transfer app.

FWIW, I don't have this problem when using my phone (Samsung Galaxy S4 - Android 5.0.1).