After a restart, I am able to play video on my phone, but after a few hours (or later in the day) when I try to play a video file it says "Sorry, this video cannot be played" - I have two video players, both say the same thing. My videos were on my SD card, and I thought maybe it was a dodgy card, so moved the vids to the internal storage, same issue. But if I restart the phone, they do play... any ideas??