Although there is no rocket science involved in installing and using an external USB hard drive on Mac OS X, yet bad luck can knock on your door anytime and when it comes, even the simplest of tasks become complicated. So if your external drive is not showing up on your Mac OS X, then try these tricks to resolve the issue. Chances are you are doing something wrong, making a simple process a lot more complicated.
Check for the Obvious Mistakes
Check for other most obvious problems instead of reaching to the conclusions. Make sure that the USB is plugged in properly. It’s best to take the USB out and insert it again. Wait for a few seconds as the OS normally takes some time in detecting the external drive. To be on a safer side, go to File > New Finder Window> Devices. If the hard drive is still not showing up under the Remote Disc section, then try a different port.
Check if Hard Drive is being Mounted
Connecting the external hard drive is different from mounting it. The contents of a hard drive show up on Mac OS X only when it is mounted, not just connected. Go to Utilities for checking Disk Utility. If you see the hard drive on the left side, then highlight the volume and press the Mount button. This may resolve the issue. Now, go back and check Devices in Finder window. The mounted hard drive should be showing up there.
Make Sure Hard Drive is Getting Enough Power
If the above-mentioned solutions do not work, then chances are the hard drive isn’t getting the power it requires to start working. USB provides 5V power to the hard drive, but some drives require more power than that. Try a USB power cable to resolve the power issue. It will give additional power so that the hard drive can start working.