How to Recover Data From External Hard Drive Not Showing Up?

If your external hard drive is not showing up, start by checking the USB cable, power and connector ports on your external drive. Plug the drive into another computer to see whether the issue is caused by the drive itself or your system. In case of using Windows, run Disk Management and look to see if the external drive is detected but without the drive letter. If the drive is detected in such a way, assigning a drive letter to it might help you get access. Should the drive be unallocated or prompt for formatting, refrain from any actions until attempting data recovery.