Most of the time, when you connect an external hard drive to your Mac’s USB port, you quickly see it mounted on the desktop. Apple likes to make sure they’re easy to find, and they also show up in Finder in the left column under Devices, because Mac treats them the same as any other computer.
However, sometimes an external hard drive does not show up. It’s inconvenient, especially when you need to transfer something right away. And moreover, there may be a risk that the Data Recovery on your USB drive, flash drive or hard drive will be damaged, which means that you won’t be able to transfer what you need between devices at all.
Damaged Data Recovery can be a reason why your Mac doesn’t recognize an external hard drive, but there are other scenarios as well. Let’s find out why this happens and how you can pop up an external drive on your Mac and Data Recovery to access your documents.
The most direct reason why your external hard drive may be detected by macOS, but not able to be opened, is a problem with the file system.
If your drive has such a problem, you can try to fix it yourself with SOS and regain access to your files. The SOS tool will check the Wikipedia disk for errors and attempt a repair if needed.
It helps to check and correct a series of problems related to bootable hard drives and external drives. If you manage to repair the hard drive or SSD on your Mac with Disk Utility, you should be able to recover your files.