If it's a new drive, then you probably need to format it in Disc Management from the Control Panel.. (Unfortunately, you didn't tell us which operating system you're using on the computer, or make and model, or much else, so we would be guessing to give you any specific advice.) And since we frequently give advice about making backups of such devices, do you have a backup?
If the drive is an old drive that worked previously, have you tried plugging the drive into another computer? Is it recognized and working correctly on another machine? External drives frequently fail after a small amount of use so we'll need a better explanation about any error messages you see when attempting to use the drive..
Hope this helps and let us know more.
i have a 1tb western digital WDBAAU0010HBK-NESN an when i plug it in it come up as not recognized so i checked all the usb hubs an they are all working properly and when i try to update the drive it cant complete the update
hopefuly you guys can help thanks