You connect your external drive, hear the USB chime, and then nothing. No drive on the desktop. Nothing in Finder’s sidebar. It’s like the Mac doesn’t know the drive exists.

This is a different problem from a drive that won’t eject. Here, the drive won’t even show up. But the two problems are related, and understanding why drives disappear helps you understand why they get stuck later.

Check the obvious first

Before diving into troubleshooting, confirm the basics.

Is the cable fully seated on both ends? USB-C cables can feel connected when they’re only partially inserted. Pull the cable out and push it back in firmly.

Does the drive work on another computer? If you have access to another Mac or a Windows PC, try it there. If the drive doesn’t appear on any computer, the problem is the drive or the cable, not your Mac.

Try a different cable. This one step resolves a surprising number of “drive not showing up” problems.

Try a different port on your Mac. If you’re using a hub or dock, connect directly to the Mac.

Does the drive need external power? Some desktop external drives require a separate power adapter. If the power light on the drive isn’t on, no amount of software troubleshooting will help.

Check Disk Utility

Even when a drive doesn’t appear in Finder, it often shows up in Disk Utility. Open Disk Utility from Applications > Utilities.

In the sidebar, look for your drive. Disk Utility shows physical disks and their volumes. Your drive might appear as a physical disk without any mounted volumes. Or it might show volumes that are grayed out.

If you see the physical disk but no volumes, the drive might need to be formatted. Click the drive and choose Erase, then select a format (APFS for Mac-only use, exFAT for cross-platform). Be aware that erasing deletes all data on the drive.

If you see volumes that are grayed out, try selecting one and clicking Mount. This manually mounts the volume, making it appear in Finder.

If the drive doesn’t show up in Disk Utility at all, it’s not being recognized at the hardware level. Try the cable and port troubleshooting above.

Check Finder preferences

Finder might be hiding your drive deliberately. Open Finder, go to Finder > Settings (or Preferences on older macOS), and click the General tab.

Make sure “External disks” is checked under “Show these items on the desktop.” Then click the Sidebar tab and confirm “External disks” is checked under Locations.

This catches people after macOS updates, which can sometimes reset Finder preferences. Your drive was mounted the whole time, just hidden.

Check for filesystem damage

If the drive shows in Disk Utility but won’t mount, the filesystem might be damaged.

Select the drive’s volume in Disk Utility and click First Aid. This runs a filesystem check and attempts repairs. For APFS volumes, the repair process is quite capable. For exFAT or FAT32, the repairs are more limited.

If First Aid reports errors it can’t fix, you may need to use the Terminal for a manual check. First, make sure the volume is unmounted (it needs to be unmounted for fsck to work):

sudo diskutil unmount /dev/disk4s1
sudo fsck_apfs -y /dev/disk4s1

Replace disk4s1 with the correct device identifier from Disk Utility. Select the volume and check the device identifier in the information panel.

If the filesystem is severely corrupted, data recovery software might be necessary before reformatting the drive.

Check System Information

For a hardware-level view, open System Information (hold Option and click the Apple menu, then select System Information). Navigate to USB in the sidebar and look for your drive.

If the drive appears in System Information but not in Disk Utility, there’s a communication problem between the system’s hardware layer and its disk management layer. Try restarting your Mac.

If the drive doesn’t appear in System Information at all, the Mac isn’t detecting the hardware. This points to a cable, port, or drive hardware problem.

The disk arbitration daemon

macOS uses a service called diskarbitrationd to manage disk mounting and unmounting. If this daemon encounters an error, it can refuse to mount drives.

Restarting the daemon can resolve mysterious mounting failures:

sudo launchctl kickstart -k system/com.apple.diskarbitrationd

Warning: this may temporarily disrupt disk management operations, including diskutil commands. Save any open work on external drives before running this command.

Encryption and APFS container issues

If the drive is encrypted (FileVault or APFS encrypted), macOS should prompt you for the password when you connect it. If the prompt doesn’t appear, the drive mounts in a locked state and remains invisible in Finder.

Open Disk Utility, find the encrypted volume, and try to mount it manually. You should get the password prompt.

APFS containers can also cause confusion. An APFS drive might show multiple volumes in Disk Utility: a container, a system volume, and a data volume. If only some of these mount, the drive might appear partially or not at all in Finder.

Prevention and maintenance

Run Disk Utility’s First Aid on your external drives periodically, even when they seem fine. Catching filesystem issues early prevents the “won’t mount” scenario.

Always eject drives properly before disconnecting. Improper ejection is the leading cause of filesystem corruption that later prevents mounting.

If your drive mounts successfully, Ejecta helps keep it that way by making sure you can always eject cleanly before disconnecting. Preventing improper ejections means fewer filesystem errors, which means fewer times you plug in your drive and stare at an empty desktop wondering where it went.