Why Is Your Mac Not Recognizing an External Hard Drive?
There are several reasons why an external drive might not appear on your Mac, and the majority are not catastrophic. One of the simplest explanations is the USB cable isn’t securely connected to your Mac, to the drive, or both. Another reason could be the USB port you’re using is no longer functional. You might also have a faulty USB cable. In some cases, the problem can be fixed with nothing more than a quick reboot of the system. However, you might also have a faulty external drive—a problem that will likely require replacing the hard drive.
How to Fix an External Drive Not Showing up on Mac
If you’ve connected an external drive to your Mac computer and it doesn’t show up as an available option, there are a few things you can try to make the drive show up and gain access to it. One of the most powerful functions of the Disk Utility is the FirstAid tool, which allows you to repair damaged or nonfunctional drives. If the external drive appears but doesn’t allow you to read or write from it, running FirstAid gives you the ability to possibly save any data stored on the drive. Recent updates to macOS have made it so most external drives can be read, but you can’t write to them without additional software. However, if a drive is formatted for a different system, it might not appear on macOS. In this case, you will need to reformat the drive.
