I have an ASUS Fonepad 7 with a 64gb external sd. Most of my apps are installed in my external sd. All were working fine when I was running on Jellybean. When the system upgraded to Kitkat recently, I always get an alert that my external storage was disconnected unexpectedly. It would reconnect by itself but eventually would get the error again. Sometimes, the screen blacks out completely and the only way it could turn bck on is when I would physically unmount the sd card. Power cycle and even hard reboot is not fixing it.