How to fix the disk you inserted was not readable by this computer in macOS?
I stored the important data on my external hard drive, one day, when attempting to access it and I get a message: "The disk is unreadable by this computer, do you want to initialize the disk?"
If you are using the latest Mac OS X operating system, the above error message will be: "The disk you inserted was not readable by this computer with three options: Initialize, Ignore, or Eject?"
What causes "The disk is unreadable error"?
"The disk is unreadable" message usually means that the directory of the drive has become corrupted. Corruption can happen for a number of reasons:
Catalog file corruption
Internal file system errors
Disconnecting or power off the drive without unmounting it
Forcing a restart on the computer
Experiencing a software lockup while writing to the drive
Turning the computer off without doing a proper shut down
Solution 1: Fix "Disk is unreadable" error with First Aid
First Aid is a utility built-in the Macintosh operating system for checking and repairing file system errors.
Step 1: Please open Applications -> Utilities -> Disk Utility.
Step 2: Select the unreadable disk from left panel.
Step 3: Run First Aid to fix unreadable disk. If First Aid fails to repair unreadable disk, please go to solution 2 to recover data from unreadable disk.
Solution 2: Fix"The disk is unreadable" error by data recovery
Due to the above causes, Mac Operating System fails to read the hard drive and the data stored in it becomes inaccessible. To access the hard drive again, maybe you want to run First Aid in Disk Utility. If you are experiencing the disk is unreadable error and you have a backup of your data elsewhere, use the Disk Utility to erase the drive and then restore your data from backup. If you do not have a backup, you need to use a professional Mac data recovery software to restore data.
What's worse, when encountering "The disk is unreadable by this computer" or "The disk you inserted was not readable by this computer", you clicked "Initialzie" button to initialize the unreadable disk without knowing this operation would completely delete all your precious data from the hard drive, then in that case it is hard to recover lost data. So you need a professional Mac data recovery software.
As a professional Mac data recovery software, M3 Mac Data Recovery can recover data from unreadable hard drive, recover deleted files emptied from Trash, recover data from formatted drive, recover data from deleted/lost APFS partition, recover data from APFS drive, etc. in macOS 10.14 Mojave/10.13 High Sierra/10.12 and Mac OSX 10.11/10.10/10.9/10.8/10.7.
Tutorial to recover data from unreadable hard drive on Mac
Step 1: Download, install and launch M3 Mac Data Recovery on your Mac computer.
Step 2: Select unreadable hard drive.
Step 3: M3 Mac Data Recovery is scanning the data from unreadable hard drive.
Step 4: Select the found files you expect to recover and then click Recover to save them.
Tips: If the above solution fails, please choose the volume and try again.
Solution 3: Fix "The disk is unreadable" error by reformatting
After data recovery is successfully done, you can reformat this unreadable hard drive, external hard drive, SD card, USB flash drive, memory card, CF card, etc. to fix "The disk is unreadable by this computer" or "The disk you inserted was not readable by this computer" error in macOS 10.14/10.13/10.12 Sierra and Mac OS X 10.11 (El Capitan), 10.10 (Yosemite), 10.9 (Mavericks), 10.8 (Mountain Lion), 10.7 (Lion) with the following solution:
Step 1: Launch Disk Utility from Utilities.
Step 2: Click the icon for your hard drive in the sidebar on the left.
Step 3: Click the Erase tab along the top of the window and enter the related information.
Step 4: Click the Erase button.
Step 4: Click the Erase button to fix "The disk you inserted was not readable by this computer" error. After format completes, the unreadable drive will be working again.
Solution 4: Fix "Encrypted drive is unreadable" error on Mac
If you receive "The disk you inserted was not readable by this computer. There are three buttons: Initialize, Ignore, Eject" after inserting a encrypted drive, please choose "Ignore" and find the corresponding software to open it.
If the unreadable drive is encrypted by Bitlocker, please try M3 Bitlocker Loader for Mac.
Solution 5: Look help from a local data recovery professional
If disk is still unreadable by any Mac data recovery software, please send the unreadable disk to a local data recovery professional for help if you lost important data.