Fix ‘The disk you inserted was not readable by this computer’ on Mac

In this post, we are going to discuss on How to fix ‘The disk you inserted was not readable by this computer’ Error on Mac. This error indicates that your external hard disk drive (HDD), or USB flash drive has a detected issue. If you are facing this error, then you can this with our instructions. Let’s start the discussion.

What is ‘The disk you inserted was not readable by this computer’ Error on Mac?

This is common error associated with external storage device usually occurs due to some reasons when you connect an external drive like HDD, USB flash drive to your Mac computer. This error message appears with three buttons including ‘Eject’, ‘Ignore’, and ‘Initialize’ on Mac OS device and explained that you can’t access or open the disk you inserted.

Sometimes, this error message can be different like ‘The disk is unreadable by this computer, do you want to initialize the disk?’ but the issue is the similar. No doubt these external drives have your personal files or data and if you can’t access them due to this issue, then it can cause big privacy & security issue means any how the file recovery from this inserted disk is necessary.

If you are unable to access or open your external storage drive like external hard disk drive (HDD) or flash drive in your Mac computer, then one possible ways to access all files or data was stored on such drive is to restore them from a backup. It means if you have strong backup of your disk you inserted but showing error, then you can restore them from backup or you can use our instructions to fix and this way, you can access your disk.

Reason behind ‘The disk you inserted was not readable by this computer’ on MacOS

  • The storage disk drive is not formatted to support MacOS format. If you used this external storage drive on Windows computer previously and now you want to use this drive in MacOS, then the storage drive used in Windows must be formatted in supported MacOS format.
  • This error might occur with WD Hard Disk Drives due to race condition on 1394 bus that causes table of contents of VCD to be corrupted by another bus reset.
  • If external disk drive whether hard disk drive (HDD) or USB flash drive, if it is not formatted in files System format that MacOS support, then this error might be occur when you insert the disk into Mac
  • It might possible that external storage drive itself is corrupted or USB interface has failed to load.

How to fix ‘The disk you inserted was not readable by this computer’ Error on Mac?

Method 1: Check if the problem is in Mac or disk you inserted

Sometimes, this error might be occur if Mac computer is already faculty means problem with Mac computer can trigger this issue. To check the Mac System, you just plug-in different external hard drive, USB flash drive to your Mac, open ‘Finder’ application in Mac and check if this external drive is appeared. If yes, then the problem is related to external drive, not the Mac.

Method 2:  Check the ‘File System Format’ of your disk

If the disks like external hard drive, SD card, USB flash drive or other storage device is formatted with NTFS format, then it is not hard to understand why it s unreadable on Mac. Note that MacOS can read from Windows-formatted NTFS drives, but can’t write to them out of box. So, you can convert NTFS File System to FAT32 File System to fix this issue.

Disk formatting process will erase all data stored in disk drive. So, you should make sure that you have strong backup of your personal stored in disk you want format. To format disk’s File System NTFS to FAT32 File System, follow the steps below.

Step 1: Open ‘Disk Utility’ on your Mac computer

Step 2: Select the problematic drive

Step 3: Click on ‘Partition’ button at the top, and select the number of partitions you want on disk after formatting

Step 4: Click on ‘Format > MS-DOS (FAT)’ and hit ‘Apply’ button

Step 5: Now, click on ‘Partition’ to start the formatting.

Method 3: Repair the disk that was showing ‘The disk you inserted was not readable by this computer’ error with ‘Disk Utility’ on Mac

Disk Utility on Mac offers you can find and repair errors related to the formatting and directory structure of Mac Disk. So, you can this utility to fix this error.

Step 1: Open ‘Launchpad’ in Mac computer

Step 2: Search for ‘Disk’ and click on ‘Disk Utility’ from search results to open

Step 3: In the opened ‘Disk Utility’, select the disk that is showing the error, and click on ‘First Aid’ button from ribbon at the top

Step 4: Wait to complete the process. Once done, reboot your device to see the changes and check if the problem is resolved.

Method 4: Fix MacOS High Sierra – Clover Bootloader Bug (For macOS High Sierra users)

If you are facing ‘The disk you inserted was not readable by this computer’ error while running Hackintosh MacOS 10.13.x High Sierra with ‘Clover Bootloader’, then you can follow instructions below to fix.

Step 1: Open your browser and download ‘Patch no readable disk’ file as patch from official site or you can download it from ‘Mega For Business’ Official page

Step 2: Once downloaded, open ‘Finder’ application in Mac computer

Step 3: Navigate to ‘MacOS > System > Extensions’

Step 4: Drag and drop the .kext file presented in patch folder inside ‘Extensions’ folder

Step 5: Once the extension has been replaced, use the Search function to find and open ‘Terminal’ application

Step 6: In the opened ‘Terminal’, type the following command one-by-one and hit ‘Enter’ key after each to execute

sudo chown -R 0:0 /Library/Extensions/AppleAHCIPort.kext && sudo chmod -R 755 /Library/Extensions/AppleAHCIPort.kext

sudo touch /System/Library/Extensions && sudo kextcache -u /

Step 7: Once done, restart your computer to see the changes and check if problem is resolved.


I am sure this post helped you on how to fix The disk you inserted was not readable by this computer with several easy methods. You can read & our instructions to do so. Note that backup plays important roles in data recovery in case of damage. So, you should create and keep regular backup of your personal files or data stored in either internal or external storage media. That’s all. For any suggestions or queries, please write on comment box below.

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