Back up issues

Hey what up guys,

I’ve got an external hardrive and i wanna back it up. I’m using the Nero back it up application. I select the target as the C drive and the target path my i drive (external hard drive). The moment i select my i drive on the target path my target changes to my i drive. I’m really not sure what else i’m suppose to do. Any help will be appriciated. :confused: