Ah!

I had completely forgotten an incident that happened about 2 years ago. I was on a course and was given a ‘state of the art’ 8GB MP4 player to use for recording speeches, conversations and the like. After the course I decided to put some stills and videos on it. The details are very hazy but I had similar problems with the differing FAT systems. As far as I can remember I formatted it within the MP4 as Windows didn’t recognise it.

So, thanks to you, I can add “Check the file structure of the device” to my list of USB solutions.

Incidentally, that MP4 player is stuffed in a drawer somewhere along with all the other 'useless' gadgets I have bought or been given and only used once.

EDIT: I've just retrieved the said player and it is formatted to FAT32. It's playing Sloop John B by the Beach Boys, now Elizabethan Serenade by Mantovani. It's quite good, I might bring it back to life.