My nook tablet stopped transferring files from my computer. Very frustrating. I use a Mac. I tried everything including deauthorizing my Nook and registering it again. That did not work. So I deleted my alternate method - an android transfer application (which also no longer worked with the Nook), reloaded it, and it finally worked again. The transfer app can be found here -
https://www.android.com/filetransfer/. Th original Nook still does not connect to my computer but the android app now does work as long as I start the app before connecting my Nook to my computer. I am very very disappointed with B&N.