Can anyone please help. I back up on to two separate cloud servers but want the reassurance of using time machine to back up on to an external hard drive. Reasonable wish I think. I have a five year old G-technology 1tb mini external hard drive. This has fire wire ports. The macbook air does not. So I just bought from the apple store a fire wire to thunderbolt adaptor. This does not seem to work with the mackbook air. The external hard drive just makes some worrying clicking sound and then turns off and then attempts to start again. What's going on?