Seagate External Hard Drive Not Working On Mac Title Image

Many Mac, and Mac Pro users have a Seagate external hard drive and use it to expand their Mac’s internal storage.

But what if your Seagate external hard drive stops working?

Take a run through this list of ways of get your drive working again.

Seagate External Hard Drive Not Working On Mac Fixes

Streak through the things to check to find out what works for you.

1. Check Your Mac Is Set To Show External Disk On Desktop.

When you’ve plugged in your Seagate external drive and nothing. No drive icon shows up on your Mac.

Seagate Drive Icon

Especially when it’s the first time you’re using an external drive on your Mac.

The key to getting your Seagate hard drive working could be a simple setting.

It could be your Mac isn’t set up to show external disks on your desktop. And your Seagate drive is an external disk.

Open a Finder window on your Mac and pick Finder preferences from the top of your desktop.

Finder Preferences

Then click on the General tab. And check the option to show ‘External Disks’.

Finder Preferences Show External Disks

Then your Seagate drive icon will appear on your Mac’s desktop. Double click on your Seagate’s drive icon to open a Finder window onto your drive. And you’ll be fine to use your Seagate Mac drive.

2. Check For A Light On Your Seagate Hard Drive?

A Seagate Portable external drive gets its power to work from your Mac. The power comes through your Mac’s USB port.

After you’ve plugged your external drive into your Mac. You should see an LED light up on the drive.

No light? Then for some reason your drive isn’t getting any power.

And the issue points to a possibly faulty USB cable.

If your Seagate is a desktop type of drive and your Seagate’s LED isn’t lighting up. Check and replace your power cable and see if that solves your issue.

3. Are you using a USB hub? Then Try Another Port On The Hub.

That didn’t work?

Then next plug your Seagate drive direct into your Mac. You may have an issue on your USB hub.

The exception to this is if you have a particularly old Mac.

The USB standards have evolved over the years. And the power draw allowed by the latest USB standards, are much higher than they were before. Particularly if your Seagate is an SSD (solid state drive).

It could be your older Mac isn’t able to give the Seagate drive the power it needs to run. And it could be that you do need a USB hub with its own independent power. So that the Seagate hard drive can power up.

4. Can You See Other External Devices On Your Mac?

Plug in a flash drive, or thumb drive into that same Mac port. Does that device show up? If it does then.

5. Try Another USB Port On Your Mac.

Sometimes the software that sits at the port in Mac OS X. Waiting for something to be plugged it gets hung up.

This can particularly happen when you’ve used a lot of different USB devices. And haven’t rebooted your Mac computer in a while. Plugging in and out different USB devices.

Sometimes the USB port software gets stuck.

So, try plugging into another USB port on your Mac and see if that fixes the issue.

6. Reboot Your Mac.

After you’ve tried plugging into another port. And your Seagate external hard drive still doesn’t work.

It could be that your Mac just needs a reboot – a full shutdown.

Go to the top left of your desktop. Click on the Apple logo for your Apple menu and pick Shutdown.

When you haven’t shutdown your Mac for quite some time. And you’re just putting it to sleep after you’ve used it. It can get to the stage where it just needs a full power down and power up.

After you’ve shutdown. Wait more than 10 seconds and then power back on.

And that may well get your Seagate hard disk working again.

7. NVRAM Reset Your Mac.

The NVRAM on your Mac is a small amount of memory that holds certain hardware settings. And sometimes that RAM needs a clear out.

On an Intel based Mac you do this by shutting down your Mac.

Eject your Seagate external hard drive. Shutdown your Mac computer.

Then when you power on you hold down the OPTION + Command + P + R keys.

All at the same time. Wait at least 20 seconds.

Your Mac will reboot itself.

You hold down the keys until you hear the second start up chime. Or your Apple logo appears.

8. Take Your Seagate External Hard Drive To Another Mac.


It’s possible that you’ve got a hardware or software problem. Or incompatibility issue on your Mac. Or with your Mac OS (operating system).

See if your Seagate hard drive will run happily on another Mac.  What’s the difference between that Mac and yours?

That could give you a clue to where the issue lies.

If you can. Try your drive on a Windows PC. If the drive works fine on a PC. Then it maybe an NTFS drive and so set up for a PC.

9. Is Your Seagate External Drive Formatted To Work On Your Mac?

Apple File System (APFS) Or MacOS Extended (Journaled) or ExFAT. Are compatible Mac file systems.

As these are the file system formats your Mac can read and write to.

You can double check if your Seagate drive is compatible with your Mac in Disk Utility.

You can find Disk Utility in your Mac’s Applications folder. Inside the Applications folder you’ll find another folder called Utilities.

Disk Utility lives inside there.

Click on your drive under the external heading, at the top level.

Then look to the right hand side of the window Disk Utility window.

You should see your Seagate drive listed as a USB external physical disk. And the partition Map as GUID.

Seagate USB And Master Boot Record

In the screenshot above you’ll see this Seagate drive is showing as a Master Boot Record.

This confirms the format of the drive. 

APFS was originally made for a solid state drive (SSD). But you can run it on hard drives. As long as your Mac OS supports APFS drives.

Mac OS Extended Journaled has worked on Mac’s for years. Even the oldest Macs.

ExFAT is a file system a Windows PC can read as well. It’s a shareable file system. But can’t be used for a Time machine backup on a Mac.

But for each of the file systems. APFS, Mac OS Extended Journaled or ExFAT the partition Map must be GUID to be compatible with your Mac.

If the way your drive is set up is not right for a Mac. And you have files on the drive. You’ll need to look at copying them off somewhere else if you can first. And consider reformatting the drive to use it happily on your Mac.

10. Is Your Seagate External Drive Compatible With Your Mac?

When your Seagate external hard drive shows up on your Mac’s desktop. But you can’t put new files on your Seagate drive.

It’s likely not in a Mac format.

Seagate Technology sells a range of external drives. Some are in an ExFAT format. Some are formatted as NTFS.

NTFS is a disk format your Mac can read. But can’t write to.

You can check the format of your Seagate drive by right clicking on the drive icon on the desktop.

Right Click Get Info

And from the menu you pick Get Info.  A pop up window will come up with the vital statistics of the drive. And part of that information is the format.

Seagate Get Info

If it says NTFS in the format field. Then you have an NTFS formatted drive.

You have a choice. You can use disk management software on your Mac called Disk Utility. And format your drive to a format your Mac can write to.

You can find out how to use Disk Utility to format your Seagate USB drive at this post here.

But formatting wipes everything that’s on the drive. And when you mainly use the drive on a Windows PC and you have files you want on there. Then that’s not an option.

Or, you can use third party driver software on your Mac. And leave your Seagate external drive in NTFS format. There are several companies that make and sell NTFS driver software to run on Mac.

11. Your Seagate Drive Sometimes Works Sometimes Doesn’t

When you’re having strange problems on your external hard drive.

Incorrect formatting can be a cause.

I recently received a Seagate hard drive.  It was ExFAT formatted.  But with a Master Boot Record as its partition scheme.

Seagate Partition Map Master Boot Record

Macs are picky about their drives. And though your factory delivered formatting may seem to work on your Mac. Over time you can get really odd problems showing up.

Like the Seagate external hard drive working. And then not working. Or you can’t see your files on the drive.

The very safest bet with any new Mac drive is to format your external drive on your Mac. And be sure the formatting is set up right for your Mac.

12. Seagate External Hard Drive Is Suddenly Not Working On Your Mac

When you have used your Seagate external hard drive fine in the past. And you’ve got files on the drive. And now it’s not working.

You can use your Mac OS X disk management software program – Disk Utility. To see if Disk Utility can repair your drive.

Disk Utility is useful to try when you have issues:

  • Because you didn’t Eject your drive the last time you used it. And now your external hard drive isn’t working on your Mac.
  • You’re getting random reading or writing errors from your drive.
  • Or regularly, your Seagate external hard drive won’t eject properly.  

The first thing is to make sure you can see all devices.

You do this from the top of the screen. Disk Utility > View.  And pick the option to show all devices from the menu.

Seagate Disk Utility View

You’ll find your Seagate Technology drive listed under external. Look in the side bar of the Disk Utility window.

Then you click on your Seagate drive at the top level.

Seagate Click At Top Level

13. Running Disk Utility First Aid To Fix Your Seagate Drive

You can then run First Aid to see if your Mac can repair your drive.

You click on your Seagate drive at the top level. And then pick First Aid and confirm you want to run First Aid on your drive.

Disk Utility Pick First Aid

If First Aid doesn’t run the first time. You can try ejecting your drive and trying another USB port to see if it’ll run then.

That’s often worked for me.

14. Eject Won’t Work On Your Mac Seagate External Hard drive

You’ve tried ejecting your Seagate storage device but it won’t eject.

It could be that an application you’re running is still accessing the drive. And you don’t realize it.

Press command + Tab to see which apps are running. 

Try quitting your apps.

And then Eject your drive again.

15. Mounting Your Seagate Drive Doesn’t Work.

Is your Seagate external HDD not appearing on your Mac’s desktop. And you know your Finder preferences is set up right.

Is it greyed out when you look at the drive in Disk Utility?

You can click on the Mount button in disk utility, to mount your drive.

If your Seagate drive does not show the Eject symbol at both levels.

Seagate Disk Utility Mount

Click your Seagate drive at the level where it doesn’t show. And then click on the mount button to mount your hard drive.

16. Tried Everything And Your Seagate Drive Still Doesn’t Work

Have you tried everything above? Is your drive back up and running?

If it’s not, then you may well be at the point of concluding your drive is defunct. And you’ve got a corrupted hard drive that won’t work anymore.

If your files are important then. You may decide it’s worth your while trying some data recovery software. Or a data recovery service.

Seagate Technology direct offer a data recovery service that you could try. And see if you can get some or all of your files back and recover data.

But really, the best protection is having your data in more than one place.  And have a Seagate drive that’s a backup copy of your Seagate drive with your files on.

Particularly if your drive contains important files.

In Closing

I hope reading through this article sees you with your drive up and running again.

While you are here why not check out our other Seagate articles on the site?

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