Mac or MacBook Can't Recognize My External Drive

Mac or MacBook Doesn't Detect My External Drive. 7 Ways You Can Fix It!

An external hard drive is a lifesaver when you need a large amount of storage to store your files. What's great is that you can carry the drive with you wherever you go and easily move large files from one Mac to another. Due to large storage capacities, you can use your external hard drive as a storage backup for your Mac. You can use an external drive to set up Time Machine, which backups your personal data, including apps, photos, music, emails, and documents. External drives are very useful when expanding your Mac's existing storage. If you often see low disk space warning, it's best to transfer your files to an external hard drive from the internal drive as it will improve your Mac's performance.

The difference between internal and external drives is that the internal drive is connected directly to your Mac's motherboard, whereas an external drive is connected to the motherboard of your Mac from the outside to the with a cable. External hard drives are generally used for storing non-system files while internal drives store operating systems and software installation files. Although external drives are great for multiple reasons, the data stored inside can be compromised much easier than that in internal drives as it's easier to steal. While to steal data from an internal drive, the entire computer has to be taken, or it has to get infected with specific malware. External drives are also more prone to mechanical damage as they are generally moved around more.

Mac or MacBook Doesn't Detect My External Drive. 7 Ways You Can Fix It!

Using an external hard drive is relatively easy as you just need to plug one end of the data cable into the drive and the other into your Mac. If the drive needs an additional power source, a power cable needs to be plugged into a wall socket. Usually, when you connect your drive to your Mac, an external drive icon appears on your desktop almost instantly. Then you can begin moving files back and forth.

Unfortunately, sometimes Macs and MacBooks can't recognize the external drive. That can happen when you eject the external drive the wrong way by unplugging it from your Mac without ejecting it. Then when you plug it back in suddenly, your Mac can't recognize the drive. To remove your drive in a safe way, first, you need to eject it from your Mac. Just right-click on your external drive icon and click on Eject Device. Only then remove it from your Mac externally.

The other reason can be your Mac's or your drives hubs not working. They might have accumulated dirt and dust or were mechanically damaged. In that case, you need to clean them or change them entirely.

This issue can also occur if you plug your drive to fast into the hub. Many users have stated that by slowly plugging the drive into the port resolves this issue. Try to plug your external drive into the port gently and see if your Mac detects it.

If the connecting cable was damaged, it could also be one of the reasons why your Mac doesn't detect the external drive. So check your cable, dongles (if used), and any additional adapters for damage. If your drive is recognized, but it randomly disconnects without any warning, that can mean frayed or worn cables, and it's time to change them.

Another reason can be if your drive is not receiving enough power from the port. If an additional power supply is available for your drive, plug it directly into a power source. If not, try connecting the drive to another USB hub.

If your Mac still doesn't detect the external drive, check whether it's a problem with your drive or Mac. To do that, plug the drive into another Mac. If the drive doesn't mount on the Mac, the problem is likely with your drive, and if it does mount, then the problem is potentially with your Mac.

Check below for more advanced troubleshooting steps.

Table of Contents:

Check Your Settings

Before proceeding to more complex troubleshooting steps, check your settings if hard and external disks are set to be shown on the desktop.

1. Go to the upper menu and click on the "Finder" menu.
2. Go to "Preferences."

Go to Finder Preferences

3. In the "General" tab under "Show these items on the desktop", check the boxes next to "Hard disk" and "External disk."

Check boxes to show external drive on desktop

If the boxes are checked, and you don't see the external drive on your desktop, proceed to the next step.

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Run Disk Utility

Go to Disk Utility and lookup if your external drive is visible there. Run First Aid to find the issue with your drive.

1. In the upper menu, click on the "Go" menu and select "Utility."

Go to Utilities

2. In the Utility window, find and click on "Disk utility."
3. If you see your external drive in the Disk Utility window, but it shows that it's not mounted, select the drive and click on the "Mount" button.

Mount disk

4. Then, go to the upper menu and click on the Apple logo.
5. Click on "About This Mac."

Go to About This Mac

6. Go to the "Storage" tab. If you can't see your external drive there, go back to the "Disk Utility" window.

Check storage if drive is visable

7. Select the drive and click on "First Aid."
8. Then click on "Run" and wait for the process to finish.

Run First Aid on disk

The First Aid option will check the disk for errors and then repair the disk if necessary. Click on "Repair Disk" if you see this option pop up.

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Reformat External Drive

If you see your drive in the Disk Utility window but could not mount it to your Mac, you might have a disk format issue. In this case, you need to reformat the drive. PCs with Windows operating systems use the New Technology File System (NTFS). In contrast, Macs with macOS operating systems use the Hierarchical File System (HFS+). By default, USB flash drives and other external drives are formatted with the NTFS file system - this works great on PCs, while Macs can read data in the format but struggle to write it. Fortunately, you can format your external drive with the File Allocation Table (FAT32) or Extended File Allocation Table (ExFAT) file system.

Format FAT32 [on a Mac, known as MS-DOS (FAT)] is fully compatible with all versions of Windows and Mac operating systems. Therefore, even the oldest operating system versions such as Windows XP SP1 and OS x 10.5 Leopard are compatible. The FAT32 file system is also supported by  Xbox 360, PlayStation 3, and most cameras. Unfortunately, this particular file system does have file size restrictions. The maximum size of supported files is 4GB which means you can't write files larger than 4GB. Also, you can't create a startup drive for Macs within storage media that uses the FAT32 file system. Suppose you are not planning to use external storage to transfer large files or create executable partitions (such as a Mac startup drive). In that case, the FAT32 format can be a great option.

ExFAT is a file system format that has an advantage over the FAT32 file system. It has no restrictions on file or partition sizes. Therefore, you can write a 1TB size file and create partitions of 5TB within the device. Despite the improved data size, some older versions of operating systems are no longer compatible with this file system format. The oldest versions of operating systems compatible with ExFAT are Mac OS X Snow Leopard 10.6.5 or later, OS X Lion, Windows XP SP2, or later (with an additional update for exFAT support, Windows Vista SP1 or later and Windows 7.

Unfortunately, the ExFAT file system format is not supported by various cameras, video game consoles, and other devices that are able to read and/or write to external storage. If you will be using a USB flash drive or external storage device with any of these devices, the required format is FAT32. If the drive is to be used only with computers with modern versions of operating systems, the recommended format is ExFAT.

Format external drive:

1. In the upper menu, click on the "Go" menu and select "Utility."
2. In the Utility window, find and click on "Disk utility." In the Disk Utility window, select your drive.
3. Click on the "Erase" option.

Erase disk

4. Choose the disk format as ExFAT, MS-DOS (FAT), or Mac OS Extended (Journaled).

Format disk

5. Click on "Erase."
6. Then, go to the upper menu and click on the Apple logo.
7. Click on "About This Mac."
8. Go to the "Storage" tab to see if your external drive is visible.

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Remount External Drive Using Terminal

First, check if the system recognizes your drive. If it does see that the external drive is plugged into your Mac, but it doesn't show up, try to remount the drive using Terminal.

1. Then, go to the upper menu and click on the Apple logo.
2. Click on "About This Mac."
3. Go to the "Storage" tab to see if your external drive is visible.
4. Open Spotlight by pressing Command + Space keys on your keyboard.
5. In the Spotlight, enter "Terminal" to open it.
6. In the Terminal window, enter: diskutil list

Enter diskutil list in Terminal

The "diskutil list" command will display the essential information about all available drives and volumes attached.
7. Then search for /dev/disk_ (external, physical). Make sure to remember the number following after the word "disk."
8. In the same Terminal window, enter another command line: diskutil info disk(digit)

Enter diskutil info disk2 in Terminal

9. After that, eject your disk by entering the command: diskutil eject disk(digit)
10. After executing the eject command, check if it was removed by entering the command line: diskutil list

Eject disk in Terminal

If you don't see your drive in the list, that means you removed it successfully. Then remove the drive physically from your Mac.

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Reset NVRAM

Nonvolatile Random Access Memory (NVRAM) stores hard drive information. If NVRAM has encountered bugs, your external drive not showing up can be the cause of it. In this case, it's best to reset NVRAM.

1. Restart your Mac.
2. When you hear the startup sound, simultaneously hold down Command + Option + P + R keys on your keyboard for 20 seconds.
3. When you hear the startup sound for the second time, you can let go of the keys.

If you have a newer Mac, you don't need to restart your Mac to reset NVRAM. Just hold down the keys for 20-30 seconds, and the NVRAM will be reset.

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Reset SMC

If your Mac or MacBook shuts down after you connect your external drive, that means the drive consumes too much power from the USB port. If your drive can't connect to an additional power source and the issue keeps on repeating, try resetting SMC (System Management Controller).

If the battery is integrated:

1. Shut down your Mac.
2. Unplug all peripherals.
3. Simultaneously hold down Shift + Control + Option keys on your keyboard together with the Power button for 10 seconds. If you have a MacBook Pro the Touch ID button is also the power button.
4. Then reconnect your power cable and other devices.
5. Turn on your Mac.

If the battery is removable:

1. Shut down your Mac.
2. Unplug all peripherals and remove the battery.
3. Press and hold the Power button for 5 seconds.
4. Insert the battery and connect your Mac to the power source.
5. Turn on your Mac.

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Inspect The External Drive via Console

The Console app can be handy in times of trouble. It displays log information that helps to troubleshoot problems on your Mac. It won't fix the problem but will provide information to diagnose the problem.

1. In the upper menu, click on the "Go" menu and select "Utility."

Go to Utilities

2. In the Utility window, find and click on "Console."
3. Select the "Error and Faults" tab.

Inspect disk via Console

4. Plug in your external drive to your Mac.
5. Then look to see if it detects your drive or if there's an error. If no errors pop un and nothing happens, then your problem is not with the external drive.

Let us know in the comments which solution helped you fix the problem!

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About the author:

Tomas Meskauskas

I am passionate about computer security and technology. I have an experience of 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an editor for pcrisk.com since 2010. Follow me on Twitter to stay informed about the latest tech news or online security threats. Contact Tomas Meskauskas.

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