
Have you tried inserting both USB cables? Most, if not all, external harddrives have data cables that have two USB ports. The fatter cable is supposed to be for power and data transfer. The thinner cable is for backup power.
edit: If that does not work, you could also try inserting both cables and restarting your computer. That process has not failed me once.![]()
Have you tried different ports? If you have a desktop pc, sometimes the USB ports in front do not recognize external hdds even if I insert the two USBs. However, if I try to insert it at the back, it recognizes the external hdd.

I've done that many times before on multiple pcs but have not experienced that. Let's wait for others to give their take on this one while I try to find a solution for you.![]()