Summary: This post will tell you how to fix external hard drive not showing up, reading or recognizing on Mac and how to prevent data loss when external hard drive not reading on Mac.
Probably, you connect an external hard drive to Mac but it is not showing up on Mac or in Disk Utility. Don't panic! You can troubleshoot and fix the external hard drive not showing up Mac issue. Don't know where to start? We are here to help.
How to fix external hard drive not showing up on Mac
To open an external hard drive that is not showing up on your Mac, simply follow our step-by-step guide.
|External hard drive not showing up on Mac desktop||Check the power connections & other connections... Full steps|
|External hard drive not showing up in Mac Finder||Restart your Mac. Immediately press and hold... Full steps|
|External hard drive showing up in Mac Disk Utility but won't mount||Go to Finder > Preferences > General tab... Full steps|
|External hard drive not recognized by Mac Disk Utility||Launch Finder and click Go in the top menu...Full steps|
1. External hard drive not showing up on Mac desktop
Usually, the external hard drive will be automatically mounted by Mac. Then you can see it on the desktop or in Finder in seconds. But sometimes, the external hard drive is not showing up on your Mac desktop. Does this mean the external hard drive is not recognized by Mac? Probably not. On the contrary, you need to check if the mounted external hard drive is allowed to show up.
Step 1: Go to Finder > Preferences.
Step 2: Check External disks under "Show these items on the desktop". Then your connected external hard drive will appear on the Mac desktop.
2. External hard drive not showing up in Mac Finder
To show up external hard drive in Mac Finder, go to Finder > Preferences > Sidebar and make sure the "External disks" under "Locations" is ticked. Then your external hard drive will appear in Finder.
3. External hard drive showing up in Mac Disk Utility but won't mount
Let's take a look at what we can do if the external hard drive is showing up in Disk Utility but not recognized.
If the external hard drive can be found in Disk Utility, it means that your external hard drive is detected by your Mac. But since you can't see and open your external hard drive as usual, we need to confirm more information displayed in Disk Utility.
- 1. Expand the View option and choose Show All Devices.
- 2. Find and select the external hard drive that is not showing up on your Mac.
- 3. Choose Mount at the top menu bar.
You may see no partition showing up in Disk Utility but the manufacturer's name like WD and Seagate. This means the partition table (A unit of data describing the partition information on the hard disk) is damaged or lost. As a result, macOS is unable to recognize the external hard drive. In this situation, you're advised to recover important data with iBoysoft Data Recovery for Mac first, and then reformat this hard drive.
The file system manages how and where data on a storage disk is stored, accessed and managed. So it's crucial to make sure that the file system is not corrupted and it is doing a good job.
To check the file system in Disk Utility: simply select the drive you want to check, and then the disk information, including file system and storage capacity, would be displayed at right.
You could see one of the 4 possible circumstances:
The file system of the external HDD is corrupted
The file system could be damaged due to improper ejection or bad sectors. As a result, the disk information is not displayed correctly. And you are unable to mount this external hard drive on Mac. To repair this corrupted external hard drive, First Aid on your Mac is a great disk repair tool to use.
- 1. Launch Disk Utility.
- 2. Choose the grayed out external hard drive from the left sidebar.
- 3. Click the First Aid button on the top and then choose Run to confirm this operation.
If Mac is unable to recognize the external hard drive still or First Aid failed to repair the external hard drive, the file system or some core data is too corrupted to be repaired by First Aid. Here are some error reports you might receive from Disk Utility:
- File system check exit code is 8
- Fsroot tree is invalid
- APFS object map is invalid
- Invalid volume directory file count
In this case, you have to reformat it to assign a new file system to this hard drive. However, as it was pointed out before, reformatting will clean the external hard drive and erase your data on this drive. If you don't have any backup and don't want to lose the data, you are advised to recover files from the corrupted external hard drive with iBoysoft Data Recovery for Mac.
- How to recover files from corrupted external hard drive on Mac?
- How to format the corrupted external hard drive on Mac?
The external HDD is APFS formatted
If your Mac uses macOS 10.12 or earlier but external hard drive is APFS formatted, you are advised to update your macOS so that it can work with the latest file systems, software, as well as some firmware relating to USB peripherals and devices.
To update macOS, you can:
- 1. Right-click the Apple logo at top right, and then choose System Preferences.
- 2. Find and open Software Update to check for new macOS update.
- 3. Back up your important files and follow the wizard to update your operating system.
The external hard drive is Read-only Windows NTFS formatted
Even though Mac can recognize NTFS drive, you can only read NTFS without write permission. And some times, the external hard drive will not work properly. In this case, do not force the external HDD to mount in read-write mode with "LABEL=NAME none ntfs rw,auto,nobrowse" in Terminal. Changing 'fstab' is risky and unstable.
Instead, you have two other options:
- If you need to use this NTFS external hard drive both for Mac and PC, you can install an NTFS for Mac program to fix this issue without reformatting.
- If the external hard drive is used only for Mac, you can back up your important files and then reformat it to a compatible file system like HFS, FAT32 or exFAT.
The external hard drive is formatted with unrecognizable file system
Mac can't recognize non-native file systems. So, other file systems like Linux EXT3 and EXT4 would not be readable by Mac. In this case, the only solution is to reformat it to make it compatible with your Mac.
4. External hard drive not recoginzed by Mac Disk Utility
External hard drives like Buffalo Ministation, WD, Samsung, Seagate, and Lacie are connected to Mac using USB cables and ports. But if the connection fails, your external hard drive won't show up on Mac.
So, if Mac not seeing your external hard drive, check if the external hard drive is properly connected by the following steps.
Check the power connections
External hard drive requires electricity to light up, spin, and transfer data. So, if the external hard drive is lack of power, it won't show up on Mac. You can do these things to check the power supply.
- 1. For Desktop external hard drives like Seagate Backup plus and WD Elements Desktop, make sure the external hard drive is externally connected to a power socket.
- 2. For portable USB external hard drives, make sure the USB port is not wobbly, dusty, loose, or deformed. If the USB port won't work and can't supply with enough power, you can try another USB port.
If you are working on MacBook, MacBook Air, and MacBook Pro models, two things to notice.
- 1. First, make sure your Mac is not in a low power mode. External hard drives can't work if there is no enough power in the USB port.
- 2. Then, make sure the USB hub and USB-C adapter work if your Mac uses Thunderbolt 3 port. Though an authentic USB Type C adapter is better, it lesses problem if you connect the Thunderbolt portable hard drive for Mac directly to your Mac.
Check the other connections
Sometimes, the external hard drive like a Seagate hard drive is not recognized by Mac. Then, you need to check the other parts of connections as well, especially when your external hard drive lights on but is not detected or showing up on Mac.
- Check if the wire of the external hard drive is broken.
- Try to connect it to another Mac or even a PC. Possibly, it's just an incompatible USB driver that stops your removable hard drive working.
- Check the USB port on hard drive enclosure case. Sometimes, the external hard drive is not showing up due to a problematic SATA connection. So if necessary, you can ask help from specialists to open the external hard drive case and have a check.
After checking the connections, you can see if the second hard drive is detected by your Mac.
Check Application that's not compatible with the external hard drive
Chances are that some programs are stopping your external hard drive being loaded. Those incompatible programs could be the USB security app, encryption program, or any antivirus software that you installed recently. In this case, you can try to reboot your Mac in Safe mode, which only runs essential macOS items.
- Step 1: Restart your Mac (some Mac computers play a startup sound).
- Step 2: Immediately press and hold the Shift key, and then release the Shift key when you see the progress indicator.
- Step 3: After the restart, reconnect your external hard drive to the Mac and see if it is recognized. If the external hard drive is recognized by macOS in Safe mode, you should start your Mac in normal mode and then uninstall the suspicious programs that you download recently.
Check if external hard drive showing up in System Information
Nevertheless, what if the external hard drive is not showing up in Disk Utility at all? It should be some hardware problems that stop the external hard drive showing up on Mac. Don't worry! You can check and repair those problems with the following solutions.
If the external hard drive doesn't show up in Disk Utility, you can check if the Mac has detected and recognized its hardware information in System Information: Go to Applications > Utilities > System Information > USB, and then check the external hard drive information.
If you see the external hard drive showing up there but not in Disk Utility, the hard drive may be under repair by macOS. Go and check it the Activity Monitor.
- 1. Click the Launchpad and find the Other folder. Find and open Activity Monitor there.
- 2. Type and search if there is any process named "fsck_hfs" or something similar. (If your external hard drive is exFAT formatted, then it should be "fsck_exfat".)
- 3. Select that task and click the Force a process to quit button at the upper left to stop it. and Then the external hard drive should show up on the desktop of your Mac.
If the parameters of the external hard drive are not recognized correctly or even not recognized, you can move forward.
Reset your Mac's NVRAM
NVRAM is helpful to retain the information while power is turned off. If you experience issues related to these settings or others, resetting NVRAM might be helpful to get your Mac to recognize the external hard drive.
- 1. Shut down or reboot your Mac.
- 2. Immediately press these four keys in a sequence: Command + Option + P + R.
- 3. Hold the keys for at least 20 seconds and after you hear the second chime, release the buttons.
- 4. After releasing the keys, your Mac will restart and hopefully your drive will show up.
Reset the SMC on your Mac
In certain circumstances, resetting SMC can be a solution because SMC is responsible for lower-level functions like power and hardware.
Note: The method of resetting SMC is varied from models to models, so check and know how to reset the System Management Controller (SMC) on your Mac.
Let's take resetting SMC of a MacBook Air, MacBook Pro Retina, or MacBook Pro's with an internal non-removable battery as an example:
- 1. Shut down your MacBook Air/MacBook Pro.
- 2. Connect the power adapter to the Mac.
- 3. After your Mac shuts down, press Shift + Control + Option on the left side of the built-in keyboard, then press the power button at the same time. Hold these keys and the power button for 10 seconds.
- 4. Release all keys and the power button at the same time. Then press the power button again to turn on your Mac, which would take a little time.
Run Mac diagnostics to detect hardware issues
Apple Service Diagnostic is a set of diagnostic tools used by technicians to find faults. You can use it to confirm or deny your suspicions. If the external hard drive has been physically damaged, you have to send it to local disk repair center.
- 1. It is advised to disconnect all the external devices except keyboard, mouse and other useful devices.
- 2. Reboot your Mac or you can power on your Mac if it powers off.
- 3. Press and hold D button on your keyboard. Hold the button until you would be asked to choose the language.
- 4. After selecting your language, it will display a progress bar stating Checking your mac.
- 5. After completing the diagnostics, it will suggest you the solutions for the errors diagnosed.
Overview of macOS Recognizing An External Hard Drive
When your Seagate, WD my passport, Toshiba or other external hard drive is not recognized by Mac, the first thing is to know which part of the recognition process goes wrong.
So let's take a closer look at how macOS recognizes an external hard drive.
Step 1: The external hard drive is connected to your Mac.
Plugging the external hard drive into a computer will establish the hardware connection, which would supply the external hard drive with power source and data transferring capability. Visually, you can see the external hard drive lighting on and hear it spinning.
Step 2: macOS detects the external hard drive.
After the connection, the Mac would detect that a new storage device is plugged in. It's going to tell the device's type and manufacturer information, which will help macOS know how to load and read this external hard drive.
Step 3: macOS reads the external hard drive.
After recognizing the hardware information of the external hard drive, the Mac will call other system components to read the external hard drive's type and partition information. If the hard drive is readable by the Mac, a visible disk icon would be formed consequently.
Step 4: macOS recognizes the files in the external hard drive.
Once Mac successfully reads the partition information of the external hard drive, it will go further by calling related programs to recognize the file system of each partition on the external hard drive. A recognized file system will let macOS know how and where your data is stored on the external hard drive, so that it can mount this external hard drive for use.
Step 5: Mac shows the external hard drive for users.
Going so far, macOS has recognized the external hard drive. Meanwhile, other programs get notified that there is a new volume available. But to make it convenient for users to access the data on the drive, it will check the system preferences and decide if users want to automatically mount and show the external hard drive on the desktop and in the finder.
Amazing, right? You probably never know the details. Your Mac has done so many works to recognize an external storage device, while you just simply plug the external drive into the USB port.
However, if one or more steps above fail, the external hard drive would not be recognized by Mac successfully. You can't access it. In this case, we need to know why Mac doesn't recognize your external hard drive.
Understanding why external hard drive not showing up on Mac
Most of the time, Mac not recognizing external hard drives is because of the hard drive corruption and faulty connections. But other factors can make external hard drive invisible on Mac as well.
The causes for external hard drives, vary from case to case. Namely, they are:
- The USB cable is broken.
- The USB port is malfunctioned.
- The USB adapter is not working properly.
- The external hard drive is not formatted incorrectly.
- The hardware and software like disk driver need an update.
- The file system of the external hard drive is corrupted.
As a result, you plug the external hard drive into your Mac but nothing happens. It looks like that Mac is not reading your external hard drive. The hard drive won't appear on the desktop or in the Finder. But this doesn't necessarily mean your Mac not recognizing the hard drive.
To sum up
It's relatively complicated to check out why is an external hard drive not showing up/recognized/detected by macOS. If you worry about data loss in this process, you can recover all important data from the external hard drive first with the assistance of iBoysoft Data Recovery for Mac.
Moreover, to prevent an external hard drive not showing up issue, it's advised to properly eject or connect your external hard drives at any time. Besides, always backing up critical files on another drive or in the cloud would help a lot.