What is happening when the external hard drive disappears?

Answer by  Suds (20)

The computer does not acknowledge the external hard drive and so it disappears. It could be because of some missing drivers(which generally happens when you download a new program. )Secondly, at times, it could also be just because of a loose or a damaged USB Port. In any case it is a very irritating problem.

Answer by  worker9486 (12)

If the external hard drive is not appearing in Windows or a Mac, check the connection at the USB port to ensure it is plugged in. You might also try a different USB port.