Why is my Mac not reading my external hard drive?

Answered by Willian Lymon

There could be several reasons why your Mac is not reading your external hard drive. One possible reason is that the external hard drive is formatted in a file system that is not supported by macOS.

File systems like NTFS (commonly used by Windows) or HFS+ (used by older versions of macOS) are not natively supported by macOS. If your external hard drive is formatted in one of these file systems, your Mac will not be able to read it. In this case, you will need to reformat the external hard drive to a file system that is compatible with macOS, such as exFAT or APFS (Apple File System).

Reformatting your external hard drive will erase all the data on it, so it’s important to make sure you have a backup of your files before proceeding with the reformatting process. Once you’ve backed up your data, you can reformat the external hard drive by following these steps:

1. Connect the external hard drive to your Mac using a USB cable.
2. Open the “Disk Utility” application, which can be found in the “Applications” folder under the “Utilities” folder.
3. In the “Disk Utility” window, you should see a list of all the connected drives and devices. Select your external hard drive from the list.
4. Click on the “Erase” tab at the top of the window.
5. Choose a file system that is compatible with macOS, such as exFAT or APFS, from the drop-down menu.
6. Give your external hard drive a name and click on the “Erase” button to start the reformatting process.
7. Once the reformatting is complete, your Mac should be able to read the external hard drive.

Another possible reason why your Mac is not reading your external hard drive is a loose or frayed USB cable. If the cable connecting your Mac to the external hard drive is not securely plugged in or if the cable is damaged, your Mac may not be able to recognize the external hard drive. In this case, try disconnecting and reconnecting the USB cable, making sure it is firmly plugged into both the Mac and the external hard drive. If the cable is damaged, try using a different USB cable to see if that resolves the issue.

It’s also worth checking if the external hard drive is receiving power. Some external hard drives require an external power source, while others can be powered through the USB connection. If your external hard drive requires external power, make sure it is properly connected and turned on.

In some cases, there may be an issue with the USB port on your Mac. Try connecting the external hard drive to a different USB port on your Mac to see if that makes a difference. If your Mac has multiple USB ports, you can also try connecting the external hard drive to a different port to rule out any issues with a specific port.

If none of these solutions work, there may be a hardware issue with either the external hard drive or your Mac. You can try connecting the external hard drive to a different computer to see if it is recognized. If it is, then the issue may be with your Mac. In that case, you may need to consult with a professional or contact Apple support for further assistance.

If your Mac is not reading your external hard drive, it could be due to the external hard drive being formatted in a file system not supported by macOS, a loose or damaged USB cable, a power issue, a problem with the USB port on your Mac, or a hardware issue. By reformatting the external hard drive to a compatible file system, checking the USB connection and power, and trying different USB ports, you can troubleshoot and resolve many common issues.