It’s the same thing that you do with your smartphone when it’s freezing up or your game console. There is an option on your Mac to simply reset your Mac USB ports, essentially like resetting any malfunctioning device.

It may seem redundant, but it’s worth the time and effort to go through the process and ensure that everything is checked. Once again, this fix focuses on the External Discs issue and should resolve the problem if you cannot see your connected devices after checking the External Disks option in the first scenario. The idea this time is to find and checkmark External Disks in another location. If you’re still having the same problem, it’s time to delve a little deeper into the settings and see if you can’t find the source of the problem. It’s not the end-all-be-all troubleshooting tip, but it’s certainly the first option you should check over before going anywhere else. It’s possible that checking the box will make it so that you can see your external connections now. If there was no checkmark in the box when you reached the External Discs option, then there’s a reason that it’s not showing up on your desktop which may explain why it is not showing up under Finder. Either way, it’s the first place you should check, and a setting you need to ensure is enabled. You accidentally turned these off somehow, or that the Mac came out of the box that way. The Mac has settings that enable and disable Mac’s ability to detect external drives. If your Mac isn’t detecting devices when you plug them in, it’s a sign that something is going on from a software standpoint unless all of your ports are messed up, which is highly unlikely, and the odds are significantly stacked against it.

How to find a device on a mac