Typically, when you plug an external hard drive into a USB port on your Mac, you'll see it appear on the desktop (also called Mount on Desktop). You can also find it in Finder in the left column under Locations (or Devices in older versions of macOS). If your drive doesn't show up on your Mac, it's likely that it's not formatted properly, is corrupted, or is defective. Or, you may have set up a password for your drive that must be entered before connecting.
We'll show you how to determine if the reason your external drive won't mount on your Mac is a problem with the drive itself, the cable, or the port, as well as how to troubleshoot the problem and access the data on the drive.
This article assumes that you have an external drive that needs to be connected to your Mac via a USB-A, USB-C, or Thunderbolt port. If you have a NAS drive connected over a network, you should read our article on connecting NAS drives.
How to Fix Drive Not Showing on Mac
There are many reasons why your hard drive, flash drive, USB drive, or SSD is not showing up. It may be formatted incorrectly, damaged, the cable may be faulty or improper, or there may be another problem.
By executing the following steps, you will be able to identify the cause and resolve the issue of external drive not opening on Mac.
1: Edit preferences
I wish there was a really easy solution to mount a hard drive on my desktop. To check whether your Mac is set to show mounted drives on the desktop, try the following:
- Open Finder.
- Click Finder in the menu at the top of the screen.
- Click Settings (Preferences in previous versions).
- Click General.
- Make sure there is a check mark next to your external disk.
If you already have your external drive set up to appear on your desktop, continue following the steps below.
2: Check the cable
The first port of call is always to make sure you're connected, but we're confident you've done that. The problem may be with the cable.
One of the main reasons why a drive won't mount is if the drive isn't getting enough power. If your drive is powered via a USB-A cable, you must ensure that the drive is receiving adequate power. Very old Macs may require a USB power cable, a cable that splits into two USB connectors to provide sufficient power to the drive. Both connectors must be connected to your Mac. Likewise, make sure there is no external power supply that needs to be used for the drive.
Make sure there are no problems with the cable. Try a different cable for the drive and see if that solves the problem. Likewise, if you're using a USB port on a hub, make sure this isn't causing the problem.
Also, make sure there are no issues with the ports on your Mac. Try using a different port. Or, if you only have one port, try plugging in another device and see if it works properly.
3. Do you have a password?
You can protect your drive with a password the first time you use it, so check to see if the reason your drive won't mount is because the password request box pops up.
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4: Try another Mac, then try your PC.
The next step is to try connecting the drive to another Mac. If it fails to mount, you know there's a problem with the drive, and if it mounts, there's a problem with your Mac.
The next step is to try connecting the drive to your PC. If the drive is mounted on your PC, you have most likely discovered what the problem is. The drive is formatted for PC and cannot be read by Mac.
5: Access the drive using Disk Utility
If the various tests above indicate that your disk is defective, you can use Apple's Disk Utility program to access the disk and fix what's causing the problem. Here's what to do:
- Open Spotlight (cmd+spacebar), find Disk Utility, type disk utility, and then press Enter to open the program.
- Make sure your hard drive appears in the left column.
- If you see your hard drive in Disk Utility, make sure there is a volume underneath it. Once there, click on it and select Mount. If you've already mounted the drive on your Mac, you'll see an unmount option instead. (If you don't see the volume listed, your Mac won't be able to access the drive. The Mount option will be grayed out.)
- Options are First Aid, Delete, and Restore. First Aid checks your disk for errors and then repairs it if necessary. You can select this option: (Restore allows you to erase the contents of a drive and replace it with data located elsewhere. Erase deletes all data stored on the drive. If you need the data on the drive, do not select Erase or Restore!)
- Click the First Aid tab and select Run.
- After running First Aid, you may see a Disk Recovery option if your Mac finds errors that can be fixed. If so, go ahead and run the repair.
6: Change drive format
If the drive is formatted using a file system that is unreadable by Mac or there is a possibility that it is actually corrupted If you are unable to recover disk on Mac – if the latter is the case, we recommend that you follow our tutorial on data recovery here: Damaged disk.
The drive is fine, but I hope it's formatted incorrectly. Here's some background on the file format:
- Windows PCs use the NTFS file format.
- Mac computers prior to Sierra used the HFS+ file format.
- In High Sierra, Apple introduced a new file system called Apple File System (APFS).
- exFAT, or formerly FAT32, is a format that can be read by Windows and Mac computers.
To make your drive readable on Mac and PC, you need to format it using: exFAT or older FAT32. We'll explain how to do that below.
Your hard drive may have been formatted using a different file system (such as Windows PC). In this case, if you need to access the data on the drive, you'll need to connect it to a Windows PC that recognizes the drive and copy the data before moving on to the next step.
After you have retrieved the data from the drive through your PC, you can reformat the drive so that you can add the data back. Here's how to reformat your drive so it's readable on your Mac or PC.
- Open Disk Utility (follow the steps above).
- If you don't need the data on your hard drive, select the disk and click Erase.
- Choose a format before Disk Utility begins erasing the disk. You can change this by clicking on Formatting Options. Select the exFAT format to ensure compatibility with PC and Mac. Otherwise, Mac OS Extended (Journaled) is probably the best option.
- Give your drive a name.
- Click Erase, wait for your Mac to erase, then reformat the drive.
7: Try a data recovery app
If you can't access the data on your drive, you can try one of the options included in our collection of the best data recovery apps for Mac.
Recommendations include EaseUS Data Recovery for Mac, $89.95/£95.99 from Easeus, Stellar Data Recovery for Mac, $59.99/£43.99 from Stellar, or Recoverit $79.99/£69 from Wondershare.
8: Always disconnect the drive properly.
Here are some final suggestions to prevent this error from happening again:
After using an external drive, always unmount the disk properly to avoid damaging your external drive in the future. Don't just unplug the USB cable. To unmount a drive, simply right-click (Control-click) its icon on the desktop or in Finder and select Eject. Obviously, most drive problems occur when you remove a disk without properly ejecting it.
Have you decided there is no hope for your defective hard drive? We've rounded up the best Mac hard drives from the best we've seen here.