10 Fixes: External Hard Drive Not Recognized On Mac

external hard drive not recognized on mac

When you connect your external hard drive to your Mac’s USB port, you will see your hard drive is mounted on the desktop. To find out if your hard drive has been safely and successfully mounted on your desktop, you can easily look for it in the finder preferences section in the left-hand column under location.

But sometimes, the process might not be as easy as it sounds, and the external hard drive might not appear. Especially when you urgently need to transfer something, sometimes this issue might appear.

This might be a risk that the data on your external USB pen drive, hard drive, or flash drive might be corrupted, implying that you won’t be able to transfer what you need.

Having corrupted data on your drive or device can be one of the biggest reasons behind your Mac not recognizing your external drive, but there are other reasons.

Carefully read through this article and learn why such an error is showing up on your device and how you can fix this external hard drive not showing up issue.

Fixes for your external hard drive not recognized on mac:

  1. Check that your cable has sufficient power
  2. Change your preferences
  3. Try using other devices for the power supply
  4. Engage disk utility
  5. Run first aid
  6. Change the format of your HD
  7. Try plugging it in slowly
  8. Boot in safe mode
  9. Reset NVRAM
  10. Try a different Drive

1. Check that your cable has sufficient power 

In some cases, few hard drives need more power than other hard drives. This depends on different types and brands of hard drives, which provide and take more or less energy.

Normally a device, in general, requires up to 500 MA, which can be supplied by a standard USB 1.0 or 2.0. But if your hard drive needs a stronger power out, it may start working slower than expected or not connect.

You should check your USB cable if it is delivering enough power to the hard drive, and if it is needed, you must change to a more powerful connection or a different USB port for your Mac.

You may also use an external power source or a self-powered USB hub. This adds its power to the power of your Mac and resolves any issue.

As a reminder, do not forget to connect your Mac to the charger.

2. Change your preferences

In your settings section, your device might not be set to “display external hard drives. “ Hence it is important to fix that.

The steps are given below.

  1. Guide yourself to “Finder” and click on the finder button in the menu bar at the top of your screen
  2. Then click on preferences and then general.
  3. Now under the “general tab,” you will see an option “show these items on the desktop.” Carefully tick all the checkboxes next to “external disk and hard disk.” 
  4. Then guide yourself to the sidebar and click on the check box for “hard disk and external disk” over there.
location of general option

3. Try using other devices for the power supply

If you see that no matter what cable you use, the hard drive doesn’t show up on the computer, the problem might be in your Mac’s hardware.

In such cases, you may try using a Windows device or another Mac. The hard drive must work on the PC if you use a Windows device as an alternative. If the hard drive only works on your Windows PC, then it’s likely that your hardware is not formatted or compatible with a macOS device.

4. Engage disk utility

Disk utility is often regarded as the ultimate solution for many Mac problems related to external drives. This solution helps access and repair disk issues by checking partition Macs and performing additional checks across the system.

The steps to use disk utility are given below:

location of the required options in disk utility
  1. Guide yourself to “applications” and then click on “utility.”
  2. Click on “disk utility” and then click on “Views.” Then you will see the option “show all devices.” Click on that.
  3. The left sidebar will show all the “external drives.” Here you should be able to identify your hard drive
  4. Tap on the volume option for a menu to appear on the screen. If your device driver has been mounted, there will be an option to unmount the device.
  5. If you can’t see any volume list, then it is possible that your Mac can’t access the Drive at all; hence, you won’t be able to mount it or demount it.

5. Run first aid

Despite anything, you can always run the first aid program. The first aid program checks and scans the disk carefully for any errors that could potentially be the cause behind the external hard drive (external HDD) not mounting on your Mac. If any errors are found during the scan, the first aid program will try to repair them.

If you try to right-click on the devices icon, the first aid bar will display as a drop-down menu on the screen.

You will then see the “restore” and “erase” options. These options process to clear any data from your hard drive, so if you have any important documents, files, or any other data on your device, you should not let the program select them.

To launch the first aid program, you need to click on “run“ and then click on “continue.” After it completes the check, you will be shown the errors on the screen that your Mac might have found on the disk.

If the first aid program finds an “overlapped extension allocation“ error, it means that possibly some of the files on your device are corrupted. The corrupted files list will be displayed in your drive’s “damaged files” folder.

You must guide yourself to this folder to delete them all. Before deleting them, if you feel that they might contain important information, you must ensure that they are not corrupted and in no way might harm your device.

If the first aid program fails, then you have two other options. You can either run the program and repair the disk or back up all your data, change the disk’s format, and reinstall your current operating system.

After doing so, you will recover the data you have backed up.

6. Change the format of your HD

Generally, Mac uses HFS+ or APFS format. At the same time, windows computers are known to use NTFS. Both Mac and Windows devices are known to recognize FAT32 and exFAT.

You may try checking the format by guiding yourself to the Apple menu at the top left corner of your screen and then clicking on ”About this Mac. “ Then you will find the “storage” option. You may click on it and know your device format.

If you discover that your device‘s format is not compatible or not Mac friendly, then you may want to change it by following the below steps:

location of the required options in disk utility
  1. To ensure proper initiation, you must slowly plug your device’s connector into your Mac’s port.
  2. Then click on “applications.” And tap on “utilities.”
  3. Now click on “disk utility.”
  4. When the diskutil list window opens, you can see the “external hard drive” in the sidebar on the left side. Click on the external hard drive option to open the drive‘s information.
  5. At the top of the window in the menu bar, click on “erase” and select the format compatible with your Mac Device.
  6. Now start reformatting your Hard Drive.

You should know that all the contents in your hard disk will be erased during this reformatting process. Hence it is advised to keep a backup of all your files, details, and documents so that you don’t lose them in the process.

If you don’t wish to sacrifice all the data on this process, you can try reformatting it using a Windows device. All the steps to do so are given below:

  1. Connect your device’s hard drive to a Windows PC
  2. Look for your drive in the sidebar of the File Explorer window
  3. Create a separate folder on your PC and then copy and transfer all of the drive’s content to that new folder
  4. Now right, click on the drives icon, and you will see a drop-down list. Click on “format” from that menu.
  5. Now the format window will open, where you need to click on “pick a format” and choose a format that might be compatible with your Mac and Windows device. exFAT is the most updated and in demand.
  6. In the “volume label” window, provide a name to your hard drive

Click on start to initiate the process of formatting. The process would take only a few seconds until it’s done, and then you may use your hard drive on your Mac device

Make sure to transfer all the data pack from the folder on your Windows device to your disk

7. Try plugging it in slowly

A weird feature regarding most USB cables is that sometimes they connect and function better with your device when plugged in slowly. This happens due to the flaw in design in the power-up sequence of some of the USB drives.

The power contacts in the USB connectors are designed in such a way that they make direct contact with the USB port first.

Hence plugging it slowly into the USB port applies power to the USB device and gives the hard drive some extra time to initialize.

This ensures proper functioning and order of events of your hard drive. This also makes mounting your hard drive a much easier process.

8. Boot in safe mode

Booting your computer in safe mode is a solution to different types of problems that people often deal with.

You can try booting your Mac in safe mode to fix the problem of the external hard drive utility not showing up on the Mac.

This will help you with your external hard disk problems and perform different troubleshooting processes in case your computer doesn’t boot up normally.

The steps to boot your computer in safe mode are given below:

The process of booting your Mac into safe mode is the same for all MacBooks and Mac computers(iMac). It would help if you considered whether your device is an Intel Mac or one with Apple Silicon.

If you are operating on M1 macOS, the steps to start your Mac in safe mode are listed below:

  1. If your Mac computer is still in operation, then you need to click on the Apple menu at the top left corner of your screen
  2. Then Turn off/shut down your Mac
  3. You will know that your Mac computer has successfully shut down when the screen has completely gone black, and any lights (including anything in the Touch Bar) are off.
  4. Wait for a few seconds or a minute until the computer has properly shut down.
  5. Press and hold the power button on your Mac computer until you see the start options on your screen showing different start-up disks and Options.
  6. Choose your system disk.
  7. Press the shift key on the keyboard and click “Continue in safe mode.”
  8. Let go of the shift Key
  9. Log into your System
  10. When the computer restarts automatically, a login window will appear on the screen, and you will be able to see “safe boot“ in the menu bar.

If you are operating on an Intel-based macOS, the steps to start your Mac in safe mode are listed below:

  1. If your Mac computer is still in operation, click on the Apple menu at the top left corner of the screen) 
  2. Click “Shut Down” or “Restart your Mac.”
  3. Wait for about 10 seconds or a minute
  4. As soon as your Mac starts, long-press the shift key on your keyboard
  5. Let go of the shift button when you see the login window on your screen
  6. You will see “Safe Boot“ (in red font) on the top-right side.
  7. Log into your Mac
  8. The computer might ask you to type your password into Safe Mode to boot your Mac computer. Do so, and you’re good to go.
shut down mac

9. Reset NVRAM

NVRAM stands for “Nonvolatile Random Access Memory.” 

NVRAM stores local general settings like screen resolution, volume, and hard drive information. Macs firmware can primarily access this information before the device starts booting when you restart it, Macs firmware gets to access the information.

NVRAM ensures small details like keeping the volume button muted while restarting your Mac or keeping your time zone consistent.

NVRAM bugs are the source of many glitches and errors, including your USB flash drive not showing up. 

In this case, you need to restart your NVRAM. Resetting it is a very easy and generally harmless process, just like how we reset any basic custom settings on our laptop or other devices.

The process to restart NVRM is listed below:

  1. Restart your computer
  2. Press and hold the command + option + P + R when you hear the start-up sound of your device
  3. Doing so causes your Mac to restart itself again.
  4. When you hear the start-up sound for the second time, you may then let go of the keys

This process was mainly for the older Mac computers, but for newer Mac, there is no need to restart the device. Simply pressing down the combination of the command key + option + P + R key for around 50 seconds will be enough for your NVRAM to start its reset process

10. Try a different Drive

If you have tried all the above methods but didn’t help fix the issue, you may try plugging in a different external hard drive.

If your Mac recognizes another disc, then the problem might be in the drive itself. There might be any physical damage on your hard drive like you might have recently dropped it, or it might have come in touch with water.

Overall in the worst-case scenario, you will need to replace the drive.

Ways to avoid external hard drive not mounting on Mac issue

If you have carefully read through all the above points, you will have a clear idea about how to access an external hard drive on Mac and what to do if it does not mount.

To ensure that you do not end up going through the same problem in the future, you must always check that the disk is in the right format for your operating system.

How to know if your disk is in the right format for your operating system?

  1. Your desk must have a strong power supply. 
  2. The connector of the USB cable must not be damaged or worn out

However, there are several other additional points that you should follow to avoid any future complications.

1. Keeping your operating system up to date

An out-of-date operating system may cause various problems in all different areas of your computer’s functioning. Updating your out-of-date operating system improves your device’s performance, stability, and efficiency.

Updating the operating system also provides assurance and security of your Mac by minimizing the risk of your device’s corrupted files.

The steps to download and install the latest version of your operating system are given below.

location of the system preferences option
  1. Guide yourself to the Appleicontop menu bar at the top left corner of your screen and click on it.
  2. Click on the “system preferences” option and then “software update.”
  3. The software update window will open. If any update button is available, you may click on it and let your device download the update and eventually start the update process.
location of the software update option

Sometimes your device might ask for a given passcode to allow your device to run the update process.

To stay safe, you must always back up or have a copy of your device’s important files and documents or media contents before updating the operating system.

2. Check if the USB port is clean and properly connected

A dirty, rusty, or loosely connected USB port may cause the external hard drive to not show up on your Mac. It may also create short currents and issues in Reading data.

This is common for a connecter to show such issues when you have used it for a while.

This happens because the power contacts are not aligning correctly. 

In this situation, the only solution would be to get a new cable or fix the old one. If the USB port or the connector is dusty, you may try cleaning it by dusting it with a very soft and fine brush or simply letting compressed air into the port and gently wiping it with a cotton bud with an alcohol solution.

3. Try using a data recovery app

Repairing your Mac using this data recovery service can be a suitable solution. The steps to boot your Mac in recovery mode to recover data depend on your computer’s chip.

The steps to boot M1 Mac in recovery mode are given below:

  1. Turn off your Mac computer
  2. Hold and press the power button
  3. When the Apple logo appears on the screen, you may let go of the power button
  4. The access start-up options will appear on the screen. Then click on Options and then on Continue.
  5. Now you’ll be able to see the “Restore from time machine” option
  6. Click on it, and the process of restoration will begin!

The steps to boot Intel Macs in recovery mode are given below:

  1. Guide yourself to the menu bar by clicking on the Apple logo at the top left corner of the screen
  2. Click on restart
  3. Now press and hold the Command and R keys until you see the Apple logo or the spinning globe on the screen. You will be able to see the spinning clock if your Mac is trying to start macOS recovery via the internet because it might not be able to start from the built-in recovery system.
  4. Soon your Mac will display the recovery mode utility window with the following options “restore from Time Machine backup, “reinstall macOS, “get help online,” and “disk utility” with the continue button at the bottom of the window.

Select the suitable option according to your Mac and click on continue to proceed with the recovery mode process using this data recovery software.

4. Always, properly, and carefully inject the device

Removing or unplugging the drive without safe ejection can corrupt data on the device, which might make your Mac unable to recognize it shortly. Any operating system employs write caching.

When you transfer or back it up, write caching is a situation where the Apple file systems are not immediately written on your hard drive. But they are cached until all the reading operations and side writing are completed.

If the USB drive is not carefully ejected while the cache is in use, all the files and data on your device can get corrupted or damaged.

Contrastingly removing it safely clears the cache and stops all the background operations in the device, therefore, protecting it.

Wrapping Up

There are a lot of potential issues and solutions for a Mac not reading or writing on an external hard drive. This blog has mentioned many of them to help you figure out and solve the issue. But if you need further help with Mac, you must reach out to the Apple customer service team, which is available and ready to help their customers 24X7.

FAQs

Why does my external hard drive not detected by Mac?

Follow these steps to fix the issue:
1. Go to Applications and open Utilities
2. In the utility folder, select Disk Utility
3. Click on Show All Devices from the View menu at the top of the screen,
4. Select your external drive and click Unmount
5. Connect your external hard disk again

Why is my Mac not reading my external hard drive?

Your external hard drive might not be formatted in NTFS, HFS+, or another format not supported by macOS. Another potential reason can be any loosely connected or frayed USB cable. You can try changing the cable or plugging it in slowly.

How do I revive a dead hard drive?

It is best to stop using it as soon as possible if your hard drive is breaking down. Try connecting it to a different port or even a different computer to check if the problem is in the device. You can try using a different cable as well.

How do I connect my external hard drive to a Mac?

You can try connecting your hard drive with a clean USB port via a suitable cable. Make sure to get an adaptor if your Mac has a different port, such as Thunderbolt or Firewire. You can view its contents by opening the disk.