How to fix/repair "USB flash drive is not readable by this computer" error?

Posted by Katrina to Mac Data Recovery on January 17th, 2018

Hey all, I made the dumb mistake a few weeks ago by pulling out my Lexar 4GB USB flash drive while I was copying a file onto it, now I'm getting the "The disk you inserted was not readable by the computer" error whenever I put it into my Macbook Pro. I have tried fixing it with disk utility, but the "repair disk" option is greyed out when I select it. How to fix unreadable USB flash drive on Mac?

Have you tried to plug and unplug your USB flash drive again and again but still got the error message: "the disk you inserted was not readable by this computer"? Actually, this issue generally appears when we connect our USB flash drive, external hard drive, memory card and other removable devices to Mac computer and the Apple operating system is unable to recognize or read them. Under this circumstance, we are unable to access the USB flash drive as well as data stored on it.

There are a variety of factors that could be causing our external drive not readable by this computer. It could be a problem with the hardware or a corrupt partition. Luckily, we still may be able to extract the files from it. But before recovering data from unreadable USB flash drive, please take one minute to read the following tips.

The Don'ts of unreadable USB flash drive

When a USB flash drive is not readable on Mac, keep calm and stop where we are at. As any further operation will overwrite the original data saved on the unreadable USB flash drive, we will lose the chance to find the data back. So just bear in mind that the more operation we do, the less data we recover.

How to fix "USB flash drive is not readable by this computer" error on Mac?

Here are two solutions to fix unreadable USB flash drive on Mac depending on whether we have useful files on the USB flash drive or not. The first solution suits users who still have useful files on USB flash drive, while the second one is for those who don't care about files on USB flash drive.

Solution 1: If we value the lost data on the unreadable USB flash drive, perform data recovery before fixing

If we have useful data on the unreadable USB flash drive, to avoid important data loss, we can recover data from unreadable USB flash drive with free Mac data recovery software, then fix unreadable USB flash drive by reformatting.

iBoysoft Mac Data Recovery is a free USB drive data recovery software that can recover data from not readable USB flash Drive, recover data from formatted USB flash Drive, recover data from unmountable USB flash drive, recover data from corrupted USB flash Drive, recover deleted/lost files from USB flash Drive, etc. on macOS Mojave 10.14/High Sierra 10.13/10.12 and OS X 10.11/10.10/10.9/10.8/10.7.

Aside from USB flash Drive data recovery, iBoysoft Mac Data Recovery also perform well in hard drive data recovery, external hard drive data recovery, SD card data recovery, memory card data recovery, video recovery, photo recovery, audio file recovery, email recovery.

Tutorial to recover lost files from unreadable USB flash drive with iBoysoft Mac Data Recovery

Step 1: Download and install iBoysoft Mac Data Recovery on Mac.

Step 2: Connect USB flash drive to Mac computer.

Recover data from unreadable USB flash drive on Mac

Step 3: Launch iBoysoft Mac Data Recovery.

Step 4: Select the unreadable USB flash drive, then click "Next" to start scanning for lost files.

Step 4: Preview the listed scanning results, select files we need, and click "Recover" to get them back.

After data recovery, we have to reformat the unreadable USB flash drive so that it can be usable again.

Solution 2: If we don't care about data on the unreadable USB flash drive, directly fix it by formatting

Step 1: Launch Disk Utility from Utilities.

Step 2: Click the icon of not readable USB flash drive on the left part of the window.

Step 3: Click the Erase on the top of the Disk Utility window.

Step 4: Complete the related information (name, format, scheme, etc.), then click Erase button.

Still have questions?