First Aid External Hard Drive Mac


In the sidebar, select a container, then click the First Aid button. In the First Aid dialog, click Run, then follow the onscreen instructions. When the First Aid process is complete, click Done. Repeat steps 6 through 8 for each container on the storage device. In the sidebar, select the storage device, then click the First Aid button. If the hard drive still isn’t playing ball, the next step is First Aid. Run First Aid on an external hard drive. Mac’s built-in First Aid tool is designed to verify and repair a range of issues related to corrupted files and apps, startup issues, and, crucially, external hard drive problems. Here is the step-by-step guide on how you can run First Aid on your external hard drive: To start with, launch Disk Utility. You can search for it using Spotlight Search or go to 'Finder' Application' Utility' After that, you need to check on an external hard drive. Next, click on the 'First Aid' tab and choose 'Run' to begin running.

Can you bear the loss of your important pictures and files on your external hard drive when it suddenly became corrupted? Of course, you can’t. They mean irreplaceable memories and future career to you. However, the unexpected could happen due to various reasons. It is just simply the nature of the beast.


If you encountered this problem, hopefully this post can help you regain the lost files and repair the corrupted external hard drive.

What is a corrupted external hard drive?

Different from hardware damages, a corrupted external hard drive usually results from software errors. The errors may resident in the partition table, file system, root directory or large data sectors. The errors will make the external hard drives failed to be mounted, recognized or read by MacOS. Consequently, users will be unable to open the external hard drive nor access the files on it.

The corruption not only happens to external hard drives but also to internal Mac hard drive and other external devices. To fix a corrupted external hard drive on Mac, the solutions are categorized into without formatting and by formatting.

Fix a corrupted external hard drive without formatting

Formatting usually is the least wanted solution for fixing the problem, so we gather two fixes without formatting here.

  1. Verify the connection

It sounds dumb but working very well. Many times, poor connection will make the Mac/MacBook not recognize the external hard drive. Make sure the connection is clean and firm.

  • Wipe the USB port with a clean and dry towel to get rid of any dust or other material.
  • Use another USB port/cable/hub/adapter.
  • Reboot the Mac/MacBook to refresh all USB ports.
  1. Run First Aid to repair the software errors

Do you know First Aid? It is a small utility in Disk Utility for checking and repairing the minor logic errors on a disk. In this case, you can use it to repair the corrupted external hard disk.

  • Open Disk Utility through Finder and Applications.
  • Select the external hard drive at the left side.
  • Click on the First Aid button, or right-click the external hard drive and choose First Aid from the options.
  • Click Run.

If you see the messages telling you that the First Aid failed, the external hard drive is too corrupted to be fixed by First Aid.

Fix a corrupted external hard drive by formatting

When the external hard drive has been badly corrupted, formatting will be the last fix. It will remove all errors by writing a new file system on the external hard drive and prepare it as a new and blank disk for use.

Before handling the formatting, you need to make sure you have adequate backups of important files. Otherwise, you need to restore the files from the external HD first with a Mac file recovery app you trust.

Then format the corrupted external hard drive:

  • Open Disk Utility through Finder and Applications.
  • Select the external hard drive at the left side.
  • Click on the Erase button, or right-click the external hard drive and choose Erase from the options.
  • Give the external hard drive a name.
  • Choose ExFAT as the Format.
  • Choose GUIDE as the Scheme.
  • Click Erase.

After the external hard drive is completely formatted, you need to safely eject it and replug it back to the computer. The Mac/MacBook can mount and read the external USB hard drive successfully now.

How to prevent the external hard drive from corruption?

Even though disk corruption is something that will eventually happen, it doesn’t mean that it will happen soon. In fact, a lot of precautions you can take to avoid the early disk corruption.

Some tips are listed below:

First Aid External Hard Drive Mac Not Working

  • Detach the external hard drive during the shutdown and restart the computer.
  • Safely eject the external hard drive after finishing using it.
  • Don’t download any spammy-look files to the external hard drive.
  • Don’t disconnect the external hard drive during the file transferring.
  • Handle the external hard drive careful without dropping it hard or setting it in a wet, dusty or corrosive environment.

Final words

Regardless of external hard drive brands such as Seagate, Western Digital or Toshiba, the post can be applied to almost each corrupted external hard disk. In addition, if other USB drives such as memory sticks or pen drives, this post can be a good resource as well.

Mar 23, 2016·3 min read

Mounting an external disk intends to make the storage device available for macOS to perform read andwrite operations on it. Usually, disk mounting is an automatic process and happens when the external hard drive gets connected to Mac via one of the USB ports. Hard drive mounting can be done manually using Disk Utility found under Utilities folder too. If everything is working fine on the disk, it should be visible on the left-hand-side menu of Disk Utility. Select the disk and click on the mount to make it accessible by the operating system. At times, the drive may be not detected automatically. The later part of the article covers the possible issues with issues that may arise and solutions to fix the same.

After connecting the external hard drive to the Mac, it may not show up as the connected devices. Besides, the Disk Utility may display an error message saying could not mount the disk or may freeze during the mounting process. From the number of possible reasons for this to happen, below listed are a few common issues:

1. Incorrect formatting of the disk: The disk that needs to be connected to the Mac system has been formatted in Mac OS Extended (Journaled) format or other Mac supported formats. If this is not the case, the disk will not be recognized.

2. Corrupt Disk: The disk or files residing on the drive may be corrupt and are preventing the disk from being accessible on Mac.

3. Unsafe removal of the disk: The most common reason that damages the disk is removing or ejecting the drive from the system without adequately un-mounting it from the system. This corrupts the disk permissions, which will later prevent the device from mounting properly.

4. Power failure: A sudden power disruption may damage the connected disk and cause the storage device being unable to mount successfully on the system again.

5. Connecting Hardware: The SATA cable or USB through which the disk is connected to the system may be faulty and will prevent the disk from mounting.

The most commonly used resolution to fix the mount issue is to simply restart the system and connecting the disk again to check. If this does not solve the issue, DiskUtility can become a handy tool to resolve the issue.

1. Follow the basic steps of checking whether the disk is properly connected to the system and powered on if required.

2. If the disk is visible in Disk Utility but it did not mount, select the disk and click on First-Aid. This will check the disk for any errors on the disk that can be repaired.

3. If the above procedure did not work, “live verification” can be performed to fix the issue. Shutdown the system and keeping the disk connected start the system. While the system boots, press Command+R. A menu will be displayed from where Disk Utility can be selected. Select the disk and follow the procedure mentioned in the second point.

4. Sometimes, the Disk Utility may not function as desired. In this case, it can be accessed from the Terminal as follows:

· Go to Applications > Terminal

· Enter: diskutillist (This will list out the available volumes)

· Check the volume indetifier from the table that appears.

· Enter: diskutilrepairVolume [diskvolumeidentifier]

Stellar provides an easy to use a third-party solution to recover the corrupt external hard drive or non-mounting disk on macOS.

1. Mac Disk Recovery: The software performs data recovery on an unmountable volume.

2. Disk Imaging: The software is capable of creating a disk image files of a corrupt storage Mac drive.

In an event of a disk not being detected, above-mentioned manual solutions may be helpful. If the user has limited technical knowledge to work with Terminal on Mac system, third-party software such as Stellar Data Recovery for Mac comes handy with a graphical user interface.

For external disks, it is important to unmount them every time before removing them from the system to prevent the corruption that gives rise to the situation in which it does not mount again.