I was backing up some data yesterday and had a problem.

The first rule of backups should be :
Backup often (and before your data goes bad).

I’m not so good at this by try to get round to it as often as I can.

The second rule of backups should be:
Always verify your backups

This is where I could have had a problem. Fortunately I had the verify data box ticked and the bad media was detected. Running the backup again everything went smoothly. Wheew!