Is the drive formatted, and if not, or if you don't know, is there data in it? If you need to format it and has data in it, copy the data to the hard drive before proceeding to options 1 or 2.
1. Right-click your eternal drive > Select Fortmat, NTFS and Quick format, then click Start.
If that doesn't work:
2. Click the Start button > Right-click "Computer" > Select Manage > Under Storage click Disk Management > Right-click your drive and select Format > Perform quick format |