Q I bought a triple DVD set of a Puccini opera. When inserted into my Mac mini, each disk freezes when I try to play it, and I cannot even eject the DVD until I have forced DVD Player to quit. Could all three disks be defective?

A Check that your DVD player is functioning correctly with other disks, and try the suspect disks in another player.

Defective DVDs are surprisingly common, and sometimes whole batches are pressed with defects which can behave like this.

Manufacturers have also been known to cause problems when changing copy protection technology. The tech support helpdesk for the DVD label should be able to confirm whether this is plausible, or arrange exchange if they are duff.

Comments One common issue with DVDs (and CDs) is when they are handled roughly in transit prior to sale. This can damage the plastic mechanism which grips them by their centre hole, allowing them to float freely in the case and become badly scratched.

If I am buying a disk in person, I always check that the disk(s) inside have not come adrift in this way. It has saved a lot of disk exchanges after purchase, and is one of the major disadvantages of buying online.

Updated from the original, which was first published in MacUser volume 30 issue 03, 2014.