Thanks for getting back to me redwing and for your suggestions. There wasn't any problems in terms of editing the tags - I succeeded in changing the embedded artwork and was able to change, then change back, the year of the album. However, MB still couldn't play the files locally. Despite, VLC being able to play the files, and the Flac tester not finding any faults with them, I've just used the flac front end (with flac.exe ver 1.32) to re-encode them as new flac files, and lo and behold MB can read these!! So it seems there was glitch with the former files. Once again thanks for your help redwing