There could be several reasons why your external hard drive isn’t working or showing up after upgrading your MacBook to macOS Big Sur 11. In this post, we’ll talk about the common reasons and how you can fix them to access the external drive and data on Mac. We’ll also share a software method to recover data if the external hard drive is inaccessible even after trying the fixes.

Reasons for External Hard Drive Not Showing Up on Mac

  1. Issue with USB connection
  2. Incorrect visibility preferences
  3. Logical disk error
  4. Corrupt drive’s partition map
  5. Incompatible file system
  6. Bug in the macOS update
  7. Physical failure of external storage device

The above reasons or otherwise won’t let you access the external hard drive on Mac running on Big Sur.You need to troubleshoot the problem by performing the procedures presented next. If the issue is resolved, access your data from the external storage device; else, recover your data from the drive.

Fix Issue with USB Connection

Check the USB connection of the external hard drive with your Mac. Probably, reconnecting the USB cable to the same or a different USB port on the Mac, changing the USB cable, or connecting the drive to another Mac or Windows PC might fix the non-working state of the external storage medium.

Image: Try a different USB port

Set External Hard Drive’s Visibility Preferences

Check the visibility preferences of your external hard drive on macOS Big Sur. Maybe, you need to select“Hard disks” and “External disks” checkboxes under the show these items on the desktop or sidebar section in Finder >Preferences > General or Sidebar tab. Also, select “Show All Devices”from the View menu of Disk Utility(accessible from Application > Utilities > Disk Utility) to see the external drive in the utility’s sidebar.

Image: Update Settings in Disk Utility and Finder

Repair External Hard Drive

When the external hard drive is visible in the sidebar of Disk Utility in macOS Big Sur, select the drive and run “First Aid” from the top pane to repair it. If the repair succeeds, access the drive. Else, the partition map or file system of the external drive might be corrupt. Recover data from the drive, then erase it to a Mac-compatible file system format to make it work again.

Image: Repair External Hard Drive with Disk Utility

Recover Data from External Hard Drive

Data recovery from a non-working external hard drive is possible with the best Mac data recovery software on Big Sur. Using the software, select and scan the external drive, preview, and select files, and recover and save them to the Mac or another external storage medium. Once data is recovered, erase it using Disk Utility.

Image: Recover External Drive with Stellar Data Recovery

Erase Drive with Compatible File System

Possibly, the external storage drive’s formatting is incompatible with macOS Big Sur. Recover data using the method shared before. Then, open Disk Utility, select the incompatible storage medium and click the Erase tab.On the dialog window, provide Name, Format, and Scheme, then click Erase and Done. Next, restore the recovered data. The drive will work in Big Sur.

Image: Erase Mac Hard Drive

Update macOS Big Sur

Any bug in macOS Big Sur after the upgrade might also result in the external hard drive not working. So, check for software update—go to the Apple menu > System Preferences > Software Update. If a macOS update is available, click the Update Now button to install the updates. Also, update the driver software from the website of the hard drive manufacturer.

Replace Failed External Hard Drive

When the external hard drive is not visible in Disk Utility, even in a greyed-out state, the drive might have physical failure. Take a hard drive recovery service if data is essential. Else, replace the inoperative hard drive with a new external HDD or SSD.


Hopefully, the post helped you fix the non-working issue of your external hard drive after macOS Big Sur upgrade. In case the drive is corrupt, use a data recovery software for Mac to salvage the inaccessible data from the corrupt hard drive. Finally, erase the drive and restore the recovered data to the revived drive.When the drive is irreparable, replace it with a new one.