One of the most attractive features of USB drives is the convenience with which they can be used. Most if not all modern computers come equipped with at least one USB port and it is usually simply a matter of plugging the drive into the port. Under normal circumstances, you will have immediate access to the device and the data it contains.

how to reset USB ports on mac

Unfortunately, circumstances are not always normal when dealing with computers and storage devices. You might be ready to view some photos your friend sent you on a flash drive when you discover that the USB drive is not showing up on your Mac.

If your Mac won’t recognize the USB drive then you cannot access its data, rendering the device useless. Hopefully, you are not subjected to this issue very often, but if you do experience problems when attempting to view a USB drive there are some potential remedies that you can try.

10 Best Ways to Fix a USB Flash Drive That Won’t Show Up on a Mac

Let’s take a look at some of the causes of a flash drive not showing up on a Mac to determine if you can resolve your particular issue. Some of these fixes are very simple while others may involve performing data recovery on a corrupted or damaged drive.

Before trying any of these options, if it is not too much trouble, try restarting your Mac. It is often the most efficient way to deal with the occasional hardware glitch that arises from time to time. If that doesn’t work then read these other options.

0 Turn It Off and On Again

A simple restart can solve surprisingly many problems, and it takes just a few clicks and a minute or two of your time:

  1. Click the Apple icon in the top-left corner.
  2. Select the Restart option.
  3. Make sure the Reopen windows when logging back in checkbox isn’t ticked.
  4. Click Restart to confirm.
  5. Wait for your Mac to restart.
    Once your Mac is done booting up, try accessing your USB flash drive again. Hopefully, this simple fix will be all it takes to get it to work.

1 Physical Connectivity Issues

The first thing to check if your thumb drive is not showing up on a Mac is if the problem is with the particular USB port that you are using. At the risk of stating the obvious, your first move should be to try the device in an alternate USB port available on your machine.

If the device works in the second port it indicates that the first port may be damaged and may need to be replaced or repaired. However, if the drive doesn’t work in any of your USB interfaces you need to look further to determine the problem.

If another Mac is available, try connecting the flash drive to it in order to verify that the USB drive itself is not the culprit. If it will not work on different Macs then it is likely that there is a major issue with the device.

2 Check Finder Preferences

It’s possible that your USB flash drive is recognized by your Mac just fine but isn’t showing up because certain specific Finder settings have been changed. Here’s what you need to do to fix them:

  1. Open Finder and click the Finder menu.
  2. Select Preferences (Command + ,)
  3. Go to the General tab (Finder > Preferences > General) and make sure the External disks item is selected.finder general preferences
  4. Go to the Sidebar tab and make sure the External disks location is selected.finder sidebar preferences
  5. Close the Preferences window.
    Your USB flash drive should now be listed as a location in Finder and displayed as an icon on your Desktop.

3 Insufficient Power

Your flash drive may not be registering with your Mac due to an issue of insufficient power. This is especially prone to happen if you use a bus-powered USB hub and have multiple devices connected simultaneously. Your Mac or MacBook may not be supplying enough power to adequately service all of the devices.

how to open USB on mac

The solution here is to try connecting the flash drive directly to the computer’s USB port or employing a self-powered hub that eliminates the power drain on your machine.

4 Failure to Previously Eject a Drive

If your Mac is having problems identifying a flash drive it may be that you did not properly eject a drive that was previously connected to your machine. Failure to eject a USB drive before pulling it out of the port can cause the OS to view the port’s status incorrectly and may impact its ability to be identified and accessed.

5 Update Your Mac’s OS and Firmware

Checking for updates may be one of the easiest ways to open USB ports on your Mac. Firmware updates address a variety of hardware issues and the functionality of the USB ports could well be one of them.

Keeping your software and firmware up to date is good practice even if you are not experiencing problems. It is an essential step in resolving issues when they arise.

how to reset USB ports on macbook

6 Faulty System Configuration

Your system configuration might need to be reset in order to resolve the USB port problem. Here’s how to reset the USB ports on your Mac by resetting two different system components that might be impacting your ability to use the USB ports on your machine.

Reset the System Management Controller (SMC):

  • Follow these steps on a Mac:
  1. Shutdown the machine.
  2. Disconnect the power cord.
  3. Press down the power button and hold it for 5 seconds.
  4. Reconnect the power cord and turn the Mac on.
  • Follow these steps on a MacBook:
    1. Shutdown the MacBook.
    2. Connect the power cord.
    3. Hold Shift+Control+Option and the Power button simultaneously.
    4. Release all the keys at the same time.
    5. Start the MacBook.

If that does not work you can try resetting the PRAM/NVRAM. The Parameter Ram and the Non-volatile RAM contain information concerning the USB ports on your Mac.

Follow these steps to reset these memory locations:

  1. Shutdown the computer.
  2. Restart the machine while holding down Command+Option+P+R.
  3. Hold down the keys until the screen flashes and you hear a sound.
  4. Listen for the chime and let the computer boot normally.

7 Use First Aid to Repair the USB Flash Drive

Mac computers come with a useful storage device repair feature called First Aid. You can access this feature from Disk Utility:

  1. Open Finder and go to Applications.
  2. Open the Utilities folder and launch Disk Utility.
  3. Select your USB flash drive from the list of available storage devices on the left.
  4. Click First Aid in the toolbar.disk utility first aid external usb
  5. Confirm that you want to check the USB flash drive for errors by clicking Run.
    First Aid will automatically repair all errors and, hopefully, make your USB flash drive usable. 

8 View System Information

When diagnosing an inaccessible USB flash drive, it’s useful to view the information your Mac has collected about it. If the information seems off, there’s a chance that the USB flash drive is a poorly made fake: 

  1. Open Finder and go to Applications.
  2. Open the Utilities folder and launch the System Information tool.
  3. Select the USB category from the left pane.
  4. Pick your USB flash drive from the USB device tree.
  5. Check the displayed information for accuracy. system information external usb

Unfortunately, fake USB flash drives are sold in large numbers these days, and the people who buy them often realize that they’ve been tricked only when they experience the first problems, such as the inability to use the full advertised storage capacity.

9 Change the Drive File System

Modern Macs natively support Apple File System (APFS), Mac OS Extended, MS-DOS (FAT), and exFAT file systems. If your USB flash drive is using, let’s say, NTFS (Windows) or ext3 (Linux), then you should reformat it to change the file system to a supported one. Fortunately, that’s pretty easy to do:

  1. Open Finder and go to Applications.
  2. Open the Utilities folder and launch Disk Utility.
  3. Select your USB flash drive from the list of available storage devices on the left.
  4. Click the Erase button.disk utility erase external usb
  5. Give the USB flash drive a descriptive name and change the format settings if you want to (all available options are compatible with macOS).
  6. Click the Erase button to format the USB flash drive.disk utility erase confirm

Just remember that not all file systems supported by macOS are also supported by Windows and Linux. For the best cross-device compatibility, use FAT or exFAT.

10 Check for Missing Software

Some specialized USB flash drives, such as those with proprietary encryption features, may require special software to be accessible. If you suspect that this could be the case with your USB flash drive, then we recommend you visit the manufacturer’s website and see if you’ve missed some important software. 

Recovering Data From a Corrupted or Crashed Flash Drive

It may be that the reason you cannot access the data on the flash drive is due to data corruption. Using data recovery software you can attempt to restore the data if you can get the system to recognize the drive so the recovery software can work on it.

Disk Drill USB drive data recovery software for Mac is an excellent solution that gives you a great chance of recovering your files from a damaged or corrupted drive.

In order to recover data from a flash drive or other USB connected drive using Disk Drill, follow these steps:

  1. Download and install Disk Drill on your Mac. You can use the free version of the software to determine if your files can be recovered before upgrading to the Pro version of the application.
    Disk Drill
    Data recovery for free
    Your Companion for Deleted Files Recovery
  2. Attach the USB or flash drive which contains the data that is to be recovered.flash drive not showing up on mac
  3. Launch Disk Drill by opening Finder > Applications and double-clicking its icon.
    Disk Drill icon in Finder Applications folder
  4. Select your USB flash drive from the list, then click “Search for lost data.”
    Disk Drill drive selection window
  5. Wait for Disk Drill to complete its scan, then click “Review found items.”
    Disk Drill scanning screen
  6. Preview your files by hovering your mouse beside their file names and clicking the eye button that appears.
    Disk Drill preview demonstration
  7. Use the checkbox column to select the files you want to recover, then click “Recover.”
    Disk Drill recovery selection
  8. On the dialogue box that pops up, use the dropdown menu to select a location on your computer where Disk Drill will recover your files (saving it to your USB flash drive may overwrite existing data). Then, click “OK.”
    Disk Drill save dialogue

Disk Drill can be a lifesaver in situations where you cannot access files due to disk corruption or damage. It can also recover files that have been accidentally deleted or from a disk that was inadvertently formatted. It is definitely worth checking out when faced with the prospect of irretrievable data on a USB or flash drive.


In most cases, corrupted or internally damaged USB flash drives can be repaired using DIY methods. But always remember – the more you use a corrupted drive, the worse it gets. So make sure to recover and backup your data first! This also makes it easier to pull the trigger and format your USB flash drive, which is usually the most effective and straightforward method to fix a problematic flash drive.

Problems with your USB ports can be extremely annoying but can usually be resolved through one of the techniques discussed above. We hope that you regain access to your data in a timely manner.


David Morelo

David Morelo is a professional content writer specializing in the technology niche, covering a wide range of topics from consumer products to emerging technologies and their cross-industry applications. His passion for te...

Read full bio
Approved by
Brett Johnson

This article has been approved by Brett Johnson, Data Recovery Engineer at ACE Data Recovery. Brett has a Bachelor's Degree in Computer Systems and Network, 12 years of experience.