Mac Not Detecting USB Device: How to Fix the Issue

Sometimes when you connect a flash drive, external hard drive or a hardware wallet to your Mac, you don’t hear the usual click and nothing appears in Finder. It looks as if the USB port has stopped working, even though both cable and device are fine. These USB connection issues can affect any model—from MacBook to iMac and Mac mini. In this article, you’ll find a simple method to quickly restore USB device detection on macOS.

Solution

1. Open Terminal
   Press Command + Space, type Terminal and press Enter.
2. Copy the command

1. Paste into Terminal
   In the Terminal window, press Command + V or right-click and choose “Paste.”
2. Execute the command
   Press Enter, then enter your administrator password if prompted.
   Note: no characters (not even dots) appear as you type your password—that’s normal.

Running this command restarts your Mac’s USB subsystem: it clears temporary data, reloads drivers and forces macOS to rescan all ports. Afterwards, any connected device—whether a flash drive, external SSD or hardware wallet—will again appear on your desktop and in Finder. Even without deep Terminal knowledge, these easy steps let you restore USB functionality without reinstalling macOS, so you can get back to work right away.