Hello my disk utility cannot repair this disk and has advised me to back up as many of my files as possible, reformat the disk and restore my backed up files. I would be most grateful if anyone could advise me on how to do all the above. many thanks

My Book Studio Version 1.1.1.4

Wizer February 29, 2012, 9:30pm 3

If the drive is not mounting you can use a recovery software to retrieve the files prior to reformating.

Try using PhotoRec