How to fix USB flash drive not recognizing/working on macOS Mojave/High Sierra?

By Molly | Posted to Mac Data Recovery on July 9th, 2018 |

My Macbook Pro running macOS 10.13 High Sierra does not recognize one of my USB flash drives, it is not shown on desktop nor in Disk Utility. flash drive is USB 2.0 and works fine under Win10, it is formatted in FAT32. Why can't macOS High Sierra recognize this USB flash drive? Is there any way to make the USB flash drive recognizable or workable on macOS High Sierra?

USB flash drive not recognizing or working on macOS High Sierra/Mojave is a common problem that most Mac users may have encountered. It's likely to happen when we try to plug in the drive again after ejecting or unplugging it unsafely. The reasons may be due to USB flash drive damage, file system corruption, virus infection or improper operation, etc. This article will show you how to fix the unrecognizable or unworkable USB flash drive on macOS High Sierra.

Part 1: Troubleshoot USB flash drive not recognizing or working on macOS High Sierra/Mojave

Note: You can also get full troubleshooting suggestions by referring to external hard drives not mounting in macOS Mojave.

Method 1: Check if your Mac is set to show mounted drives on desktop

Go to Finder > Preferences > General and make sure the "External disks" option is ticked. The USB flash drive should be recognized and mounted then.

Show external disk in Finder

Method 2: Verify that the USB flash drive recognizable in System Information

1. Go to Apple menu > About This Mac.
2. In the window that appears, click Overview.
3. Click the System Report button to open System Information.

In the window that appears, see if the USB flash drive is listed below Hardware. If the device appears but does not work in macOS High Sierra, review the USB flash drive's documentation for further troubleshooting steps.

Part 2: Fix USB flash drive not recognizing or working on macOS High Sierra/Mojave problem

Method 1: Fix unrecognized or not working USB flash drive with Disk Utility

Disk Utility deals with errors on USB flash drives, external hard drives, SD cards and other devices.

Step 1: Go to Disk Utility.

Step 2: Select the USB flash drive from the sidebar.

Step 3: Click First Aid from the top of the window.

Method 2: Fix unrecognized or not working USB flash drive by reformatting

If Disk Utility failed, the best way to fix USB flash drive not recognizing or working on macOS High Sierra problem is to reformat it. But it will result in deletion of all the files in that drive. So make sure you have a backup, or you can rely on USB data recovery software to recover all the important documents, photos, videos etc. from the unrecognizable USB flash drive.

iBoysoft Mac Data Recovery is able to recover data from unmounted USB flash drives, recover data from unreadable USB flash drives, recover data from encrypted APFS external hard drives, recover data from APFS USB flash drives, as well as recover from formatted/corrupted hard drives including SD cards, CF cards, memory cards, WD drives, Seagate drives, etc.

Step 1: Recover data from not recognizing/not working USB flash drive with iBoysoft Mac Data Recovery

1: Download and install iBoysoft Mac Data Recovery.

2: Launch this program. Select the unrecognizable or unworkable USB flash drive and click "Next". The program will start scanning this drive for recoverable files.

Recover data from not recognizing USB flash drive on macOS Mojave

3: After the scanning process finishes, you can click the found files and preview.

4: Choose what you want to get back and click "Recover".

5: Go through the recovered files and make sure all desired files are back.

Step 2: Format the unrecognizable or unworkable USB flash drive on macOS High Sierra

1. Go to Applications > Utilities > Disk Utility.
2. Select the unrecognized USB flash drive.
3. Click Erase button and complete the process.

PS: iBoysoft Ma Data Recovery is also able to recover data from formatted drives. So it's also safe to firstly Erase the unrecognizable USB flash drive then recover data from it.

Molly

Molly is an editor @iBoysoft who frequently shares useful tutorials about data recovery for Windows and Mac.

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