Thanks STKman and TechyG.
Problem occurs on a selection of media, so it does look like a drive issue rather than media.
One thing I have noticed is that the f/w on this drive is different from others. It has rev 1.34.408 and our others are 1.42.407f
Is there a later f/w version available, or should I update the suspect drive with 1.42.407f ?
Sorry for the extra q's
Regards
Mike