Sometimes when I'm using different USB connections on my PC the external drive which I then plug in is given a different drive-name to what it was previously, depending on what else is also connected, such as D, E, F and sometimes even G drive, so could this be the cause ?

After previously having problems such as yours, all my files associated with the edit are transferred to the same folder on my main drive, including audio files and the saved project files themselves.

Only when the project has bee produced do I put the audio files back in their original folder, and move the Camcorder files to my external drive . . . and touch wood, I haven't had any problems since Trevor . . My YouTube site . . (Bristol, UK) . . My JVC GZ-HM1 Camcorder