Q My friend’s Mac mini failed, and I have put its hard disk into an external drive case. When connected to my MacBook Pro, the drive light is green, the disk can be heard spinning, but it does not mount on the Mac. Is there some way to see this drive to recover his files, or is it dead?

A There are two potential solutions. The easier and much more costly is to get a good engineer or data recovery service to look at it. They have some sophisticated tools and skills that offer the best chances of recovering as much data as possible, but will charge a lot.

You can try this on your own, using a disk recovery tool such as Prosoft’s Drive Genius 4 ($99). However if this also cannot see the disk, then it is almost certainly beyond economic repair. Before consigning it to recycling, check that all connectors in the case are fully home: there is a small chance that gentle but firm wiggling will make a poor connection and it could magically come to life.

If the drive contained any sensitive or personal data, you should ensure that it is physically destroyed before disposal, to prevent anyone else from recovering data from it.

Updated from the original, which was first published in MacUser volume 26 issue 17, 2010.