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25 October 2019  Amanda J. Brook  Senior Product Manager
 

Summary
HDD, hard disk drive, is the basic storage device in computer. Especially the external hard drive is very convenient for users to carry data along with them. Yet, some Mac users said that the external hard disk is not showing up when connected to the computer. In this essay, we will analyze this situation and tell you how to solve the problem.



Why External Hard Drive is not Showing up in Mac OS

Currently, two main operating systems are used in personal computers, Windows and Mac OS. Correspondingly, hardware and software are designed based on these two systems. In Windows, the external hard drive transfers data in the NTFS format while HFS is applied to Mac OS. If you want a file system accepted by these two systems, you should use exFAT.

As Windows attracts more users than Mac OS, most of external hard drive suppliers utilize NTFS and exFAT as the file systems. But they are not recognized by Mac OS.

Besides, you can follow these steps to check as the external hard drive is not showing up in Mac OS:

1. Check whether the external hard drive has been plugged in correctly.
2. Check whether the external hard drive has power supply.
3. Check whether the cable has been damaged.
4. Reboot the computer and check whether the operating system has been faulty.
5. Change another port and check whether the USB port has bad contact.
6. Check whether the external hard drive can be recognized by Windows.

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How to Fix the Error “External Hard Drive is not Showing up in Mac OS”

If you find that the external hard drive is still not showing up in Mac OS after these steps, you should turn to check the drive. Here are some solutions.

With Windows PC

1. Connect the external hard drive to a Windows computer. Open [This PC]and see whether the drive is visible. If so, right-click at it and select [Format].
recover data from formatted sd card select to format sd card if you dont't know how to repair a undetected micro sd card
2. Then, change the file system to be [exFAT], compatible with both of Windows and Mac OS. Next, click [Start] to format it. Finally, connect it to your Mac for use.
format to exfat external hard drive is not showing up in mac

With Mac PC

1. Connect the external hard drive to the Mac and open [Disk Utility] in Launch Pad.
open disk utility in macos
2. At the left pane, if you find your target drive is grey, it is not a mounted one. Then, click the button [Mount] at the top.
mount hard drive when it is not showing up in mac
3. After that, like the below image, “Mount” will be turned to be “Unmount”.
click to unmount disk in disk utility
4. If you don’t’ see the above image, you should consider whether there is something wrong with the file system. About changing the file system, go to [About This Mac] in the Menu.
find about this mac in menu
5. Select [System Report].
go to mac system report
6. Click [Storage] at the left pane. Find out the target external hard drive and view the file system.
check disk file system in Mac
7. If the system is not [exFAT] or [HFS], please go to [Disk Utility] again and highlight this drive. Then, click [Erase] at the top.
erase hard disk drive when it is not showing up in mac
8. Select [Mac OS Extended (Journaled)] in [Format].
Encrypt USB Drive in Mac OS erase the disk and change the new format in mac

The Fix to Damaged External Hard Drive in Mac OS

1. In [Disk Utility], select the target hard drive at the left pane. Then, click the button [First Aid] at the top and then click [Run].
find first aid in disk utility
This function can check and fix the damaged files, applications, boot issues and the other errors of external hard drive.
run first aid in mac disk utility

How to Recover Formatted Data?

If you have stored some important but not backed-up files in the external hard drive, you will lose all of them through the above steps. At this situation, Renee Undeleter can help you! This software is specialized in data recovery, from various file types to the formatted hard drive.

It is designed with three scan modes, fast partition scan, whole partition scan and whole disk scan. Users, newbies included, can meet with their needs with the easy steps and clear interface.

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Easy to use Only simple steps to recover data from storage devices.

Multiple scan modes Fast partition scan, whole partition scan and whole disk scan for different recovery needs.

File types Support to recover pictures, videos, audios, documents, mails, etc.

Supported storage devices Recover data from recycle bin, SD card, external disk, etc.

Supported systems Windows 10, 8.1, 8, 7, Vista, XP, 2000 and Mac OS X10.6, 10.7, 10.8.

Easy to use Only simple steps to recover data from storage devices.

Multiple scan modes - 3 scan modes for different recovery needs.

Supported storage devices Recover data from recycle bin, SD card, external disk, etc.

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3000 users have downloaded Renee Undeleter and found data back!

1. Open Renee Undeleter and select [Whole Partition Scan].
select whole partition scan in renee undeleter on mac
2. Select the target partition and click [Next] to go on. Then, select [Fast Scan] or [Deep Scan].
click to select a target drive in whole partition scan in renee undeleter on mac
3. The scan time depends on the capacity of the disk. It takes a longer time to scan the larger disk. At last, select the target scan results and click [Recover] to save them.
double click to select files in whole partition in renee undeleter on mac