I agree with you that the USB comms seem to be ok, the files I was trying to save as a test were the default PR804 set up files, so no confusion over KN7000 files. As I say what I find confusing is that during the process I get the correct display screen (yellow text saying the transfer is in progress) and the files even appear on the desktop (I was using the desktop for the file location for the purposes of the test) but then the error message appears and the files disappear from the desktop. Very confusing.