WD Passport 1TB USB 3.0 Time Machine external HD not being recognized on Yosemite

After upgrading to Yosemite my external HD is not being recognized. My HD is a WD My Passport 1TB USB 3.0 and I have a MacBook Pro Late 2011

• It does not show on Finder


• It does not show on System Information


• It does not show on Disk Utility (even after using the Debug menu)


• It does not show on /Volumes

Do you have any ideas why is this happening? Should I reformat my drive?

Thanks!