FIX: External Hard Drive Not Mounting on macOS

FIX: External Hard Drive Not Mounting on macOS.

When you plug an external hard drive or SSD into your Mac, you expect it to automatically mount and show up on your desktop right away. However, drive errors, USB hubs, faulty cables, and a host of other reasons can prevent this.

So if you are having issues with an external hard drive not showing up on Mac, then use the fixes below to fix the issue. This troubleshooting guide also applies to USB drives.

Check Your Desktop Preferences

Is your external drive showing up in Finder but refusing to show up on the desktop? This is easy to fix. You just need to activate a certain setting in the desktop settings.

1. Select your desktop or open Finder.

2. Select Finder > Preferences from the menu bar.

3. On the General tab, check the External drives box.

Relaunch Finder

If the drive doesn’t appear on your Mac desktop or Finder (or both), try forcing a Finder restart.

1. Go to your Mac’s desktop and press Command + Option + Escape. This should trigger a force close apps popup.

2. Select Finder > Relaunch.

3. Select Restart to confirm.

Disconnect & Reconnect Drive

It sounds obvious, but you can accidentally eject an external hard drive or solid state drive. So if you haven’t already, just unplug your drive from your Mac’s USB port and try plugging it back in.

Restart Mac

Another quick solution involves restarting your Mac. This is the best way to fix any system glitches that are preventing removable drives from showing up on your desktop or Finder.

1. Disconnect your external hard drive or solid state drive from your Mac.

2. Open the Apple menu and select Restart.

3. Uncheck “Reopen windows when I log in again” and select “Restart”.

4. Wait for your Mac to finish restarting your desktop.

5. Connect the external drive again.

Connect Directly to Mac

Removable hard drives and solid state drives do not work well with external USB hubs. So if you’re using a USB hub on your Mac, try connecting the drive directly to a USB port on the Mac itself to make sure it’s getting enough power.

Note. A removable drive may require additional power to function. In this case, be sure to connect any additional USB cables to your Macbook, iMac, or Mac mini (or external power if needed).

Switch USB Ports

If you’re not using a USB hub, try connecting the drive to a different USB or Thunderbolt port instead. It is also recommended that you prevent other USB peripherals (other than wired keyboards and mice) from being connected while the external drive is connected.

Use a Different Cable

A faulty USB cable (or USB-C adapter) is another reason why an external drive cannot make a proper connection. Try a different USB connector and see if there is a difference.

Check the System Information App

Then check if the external drive is showing up in your Mac’s System Information app.

1. Open the Mac launcher and select Other > System Information.

2. Select Storage from the sidebar.

3. Check if the drive is displayed in the “Volume Name” column.

If so, you are probably dealing with disk errors, a broken or incompatible file system, or corrupted PRAM or SMC. Keep making the rest of the fixes.

Repair External Drive in macOS

If an external hard drive or solid state drive shows up in system information, it should also show up in Disk Utility. Use the opportunity to run first aid.

1. Open Disk Utility by choosing Other > Disk Utility from the Mac launcher.

2. Switch from Mac hard drive to external drive on the left sidebar.

3. Press the “First Aid” button.

4. Select Run.

5. Wait while Disk Utility scans and fixes any disk errors. Then select Done.

Alternatively, try connecting the drive to another Mac and use the instructions above to resolve drive errors.

Repair Disk Errors in Windows

If your external drive uses a Windows-compatible file system (such as FAT32, ExFAT, or NTFS), you may achieve better results by restoring it using a PC.

1. Connect the drive to your Windows PC.

2. Open the Start menu, type “Disk Management” and select “Open” to launch the Disk Management application.

3. Locate the drive in the Volume column. Then right-click it and select “Properties”.

4. Click the Tools tab.

5. In the Error Checking section, select Check.

6. Select Scan and repair disk.

Install Support Software or Drivers

Your external drive may not work with macOS unless you install third party supporting software or device drivers. For example, Seagate hard drives and SSDs may require the Paragon driver for macOS to function properly. Please refer to your drive’s user manual or manufacturer’s website for compatibility information.

Note. If you have already installed related supporting software or device drivers, it is best to uninstall them and reinstall from scratch.

Reset NVRAM or PRAM

Damaged NVRAM or PRAM (volatile memory that stores important system settings such as time, date, and startup options) can also prevent external drives from displaying. If you’re using an Intel Mac, try resetting your settings.

1. Disconnect your external drive.

2. Turn off your Mac.

3. Press and hold Command, Option, P and R and press the power button.

4. Keep holding until you hear the startup beep twice (or until you see the Apple logo a second time).

5. Plug the drive back in when you get to your Mac desktop.

Reset SMC

Another fix for Intel-based Macs involves resetting the SMC. The SMC (Storage Management Controller) is a subsystem that manages many low-level activities such as power and battery management.

The procedure for resetting the SMC is different for different Mac models. For detailed step-by-step instructions, see our complete guide on how to reset SMC on Mac.

Update Mac

Your Mac may not be compatible with the external drive’s file system. For example, Mac computers running macOS Sierra or earlier do not support the APFS file system. If possible, try updating or upgrading your operating system.

If you’re using macOS High Sierra or earlier, you can update your Mac through the App Store. On later versions of macOS, open the Apple menu and choose About This Mac/System Preferences > Software Update.

Erase the External Drive

The final fix for your external drive not showing up involves wiping the drive. You will lose all data on the device, so try copying any files or folders to another Mac or PC if possible. Either use data recovery software (or contact a data recovery specialist) to recover data from the drive.

1. Open the Disk Utility app.

2. Select your external drive from the sidebar.

3. Select “Erase”.

4. Set to Mac OS Extended (HFS+) or APFS (case sensitive) file system. If you want the drive to be readable on Windows devices, select ExFAT.

5. Select “Erase” to reformat the drive.

If the external hard drive or SSD still fails to connect, and the problem also occurs with other desktop devices, you are probably dealing with hardware issues with the drive itself. Send the drive back for a replacement if it’s still under warranty.