How to fix unreadable USB flash drive on Mac and recover lost data?

Updated by Admin to Mac Data Recovery on June 26th, 2019

I stored the important data in USB flash drive, one day, when attempting to access it and I get a message: "The disk you inserted was not readable by this computer. There are three buttons: Initialize, Ignore, Eject"

The disk you inserted was not readable by this computer

Solution 1: Fix unreadable USB flash drive with Disk Utility

macOS built-in disk utility: First Aid has the ability to fix unreadable USB flash drive error.

Step 1: Open Applications -> Utilities -> Disk Utility.

Step 2: Select the unreadable USB flash drive.

Step 3: Run First Aid to fix the unreadable USB flash drive.

First Aid built-in Disk Utility

If First Aid fails to repair the unreadable USB flash drive, please go to solution 2 to recover data from unreadable USB flash drive.

Solution 2: Recover data from unreadable USB flash drive

As a professional USB drive data recovery software, M3 Mac Data Recovery can recover data from unreadable hard drive, recover data from deleted/lost APFS partition, recover deleted files emptied from Trash, recover data from corrupted APFS drive,recover data from unmounted APFS drive, recover lost data from encrypted APFS drive, recover data from formatted drive, etc. on 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 USB flash drive

Step 1: Download, install and launch M3 Mac Data Recovery software on your Mac computer.

Step 2: Select the unreadable USB flash drive.

Mac data recovery software

Step 3: M3 Mac Data Recovery is scanning the data from unreadable USB flash drive.

Scan lost data from unreadable USB flash drive

Step 4: Select the found files you expect to recover and then click Recover to save them.

Recover data from unreadable USB flash drive

Solution 3: Fix the unreadable USB flash drive by erasing

If there is no important data stored in unreadable USB flash drive, we can directly erase it and then it will be working again after the format completes. If there is important data, we can erase unreadable USB flash drive after data recovery is successfully done. Following is step-by-step tutorial to erase unreadable flash drive on Mac:

Step 1: Launch Disk Utility from Utilities.

Step 2: Click the icon for unreadable USB flash drive in the sidebar on the left.

Step 3: Click the Erase tab along the top of the window and enter the related information.

Erase the drive

Step 4: Click the Erase button.

Step 5: Click the Erase button to reformat unreadable USB flash drive, the unreadable USB flash drive will be working again after format completes.

Solution 4: Seek help from a local data recovery service

If USB flash drive is still not readable by any Mac data recovery software, please send it to a local data recovery service for help if you have important data.

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