Weird noise before startup

Hello everyone,

I am a little worried of my new MyBook Essential 500GB ext HD. It makes weird buzzing always whenever I turn it on, and when I have it on standby and start using its files again, it makes the same buzzing noise. I am afraid that this might be a sign of hard drive failure, although the drive has been working fine for now. Is this normal or should I totally return it back?

Thank you all.