Same problem as previous people here. Have had music files on a 64gb TDK micro sd card and Power Amp played fine. Bought a Samsung 128gb card and spent a fair few hours copying files from the old sd card and an external hard drive to the 128gb card. Played fine on laptop but put in phone and Power Amp came up with "too many faied file" message's and found a lot of the folders had lost all data apart from empty folders. Tried pretty much what other posters here have done to no avail. Again it can be fine for a couple of days and then files disappear. What's going on?