If you're running out of space on your Mac, plug in one of these hard drives to expand the storage of your Mac. And even if you have plenty of space, you ought to be backing up your Mac; one of these external storage drives will be perfect for the job.

Is a hard drive the right storage option for you?

Modern Macs generally don't allow you to upgrade the internal storage after purchase, so your options include several external solutions. There are plenty to choose from, ranging from a desktop hard drive or a network attached storage device, to a portable flash drive (often referred to as an SSD, or solid state drive), and even cloud storage that you can access via the internet. 

In order to decide what sort of storage you need, you should start by answering a few questions. Do you want to be able to take your storage with you when you're travelling? Do you want to be able to access your data anywhere in the world? Do you want to be able to back up your data as quickly as possible? Or, do you want the cheapest storage solution you can get.

If speed is what's important to you, we'd recommend an SSD. SSDs are silent, smaller and lighter than hard drisk drives, and are often faster, but they are normally much more expensive. You'll find our pick of the best SSDs for Mac here.

However, if you need to get the most capacity for the lowest price, you'll want to go for a hard drive. They are generally cheaper than SSDs and offer a lot more storage.

How to choose a hard drive to suit your needs

Even within the hard drive space there are lots of things to consider. You'll want to check that the hard drive is going to be compatible with your Mac before you buy it, which will largely come down to the ports and cables it requires, for example.

NAS drives

You may also want to consider Network Attached Storage (NAS) for your hard drive, which is connected to your network and runs specialised software. These solutions often include more than one hard drive, with your data mirrored across the two. This means that if one fails, your files are still safe.

However, cheaper NAS options with just one drive are ideal for backing up and storing files without having to plug in the device. This is especially handy if you have a laptop.

RAID

Some desktop external hard drives have more than one hard drive inside. With two drives, the unit can be configured as a striped array (called RAID 0), which makes one partition of the two drives and writes and reads simultaneously for faster performance. 

However, if one of the drives dies, you lose all of your data, but the two drives can also be configured as a mirrored array (called RAID 1). Mirroring the drives safeguards your data by keeping two identical copies of your drive. The downside is that you can only use half of the unit's storage capacity.

Some two-drive external devices can also be confiugred to use the drives individually in a JBOD (Just a Bunch of Disks) setup. This way both drives mount seperately as if they were two one-disk external drives. If one drive dies, the other can continue to operate.

Speed options

While hard drives are generally slower than SSDs, there are still varying speeds available to choose from. Some drives will offer a rotational speed of 7200 rpm, while other drives spin at 5400 rpm. Pro users working with audio or video might want to consider 10,000- to 15,000 rpm for optimal performance, but these high-performance drives usually offer less storage capacity.

With that said, we round-up the best Mac hard drives (including NAS drives) here.

Apple AirPort Time Capsule

Apple AirPort Time Capsule
  • RRP: 2TB - £299; 3TB - £399, 2TB - US$299; 3TB - US$399
  • Buy from Apple

The distinctive design of the Apple Time Capsule combines elements of both a wireless router and NAS drive (network attached storage).

In fact, it's identical to Apple's AirPort router with the sole exception of having a hard disk squeezed inside it so that you can share the extra storage on your home or office network.

As always with Apple products, the AirPort Time Capsule is more expensive than most conventional NAS drives, costing £299 with 2TB of storage and a rather hefty £399 with 3TB.

However, it's packed with useful features, including the dual-band 802.11ac wifi for high-speed wireless connectivity. That makes it a good upgrade for an old wireless router - especially if your Macs and iOS devices have all got 802.11ac WiFi as well - and there are three Gigabit Ethernet ports also available for wired connections.

However, the real strength of the Time Capsule is its sheer ease of use. Apple's AirPort software is built into all Macs, so your Mac can automatically detect the Time Capsule as soon as you turn it on, and will ask if you want to set up a new network or connect it to an existing network.

You can also use it for Time Machine backups from multiple Macs, and that ease of use makes the Time Capsule an excellent option for people who don't know very much about networking.

Connectivity: WiFi - 802.11b/g/n/ac; 3x Gigabit Ethernet; 1x USB 2.0
Dimensions: 168x98x98mm
Weight: 0.94kg

Buffalo LinkStation 520

Buffalo LinkStation 520
  • RRP: £145, US$175

Apple's Time Capsule looks smart and is easy to use, but it's also pretty expensive. If you need a more affordable NAS drive that you can use on your home or office network to provide shared storage for all your Macs, PCs and mobile devices, then Buffalo's latest LinkStation model is a really good option.

The bulky black chassis may not be particularly elegant, but this two-bay drive costs just £145 for a model with 2TB of storage (make sure you select the 2TB option - there are more expensive options), which is just half the price of the 2TB Time Capsule.

There are also 4TB, 6TB and 8TB models, and even the 8TB model only costs £326, which is considerably cheaper than the 3TB version of the Time Capsule.

And, crucially, it's very Mac-friendly too - which isn't always the case with NAS drives. The LinkStation 520 supports Time Machine, so you can back up multiple Macs over your network, and there's an iOS app that gives your iPhone or iPad access to files stored on the drive too.

The LinkStation 520 also has a 'private cloud' option that lets you connect to the drive over the internet when you're away from home or the office.

Other features include a scheduling option that turns the LinkStation on or off at specified times in order to save power. If you need to add more storage you can just pop the front panel off and replace the existing drive units, and the LinkStation 520 also supports RAID 0 and RAID 1 modes as well, so that you can use it as a RAID drive if you want. 

Connectivity: Gigabit Ethernet, USB 3.0
Dimensions: 87x126x250mm
Weight: 2.5kg

LaCie d2 Thunderbolt 2

LaCie d2 Thunderbolt 2
  • RRP: £229, US$229

At first glance, the d2 drive from LaCie looks like a fairly conventional hard drive. It's a desktop drive that starts with 3TB of storage for £244, and also offers 4TB and 6TB models for £269 and £367 respectively. 

It's a neatly designed desktop drive, with a sturdy aluminium casing that makes a good match for most current Mac models. The d2 is a new model, so it includes two of the latest Thunderbolt 2 ports for maximum performance - up to 20Gbps - along with a standard USB 3.0 port as well. And, of course, you can also daisy-chain additional drives and devices off the Thunderbolt ports if you need to. 

The internal hard drive is rated at 7200rpm, so it'll be a good performer with any of those interfaces. However, LaCie also allows you to remove the back panel on the d2, and insert an upgrade card with an additional 128GB solid-state drive (£229).

The d2 then shows up as two separate drives on your desktop, allowing you to use the high-speed solid-state drive for streaming high-def photos or video files, while the larger hard drive handles your Time Machine back-ups and other types of files that don’t require top performance. 

Connectivity: 2x Thunderbolt 2.0, 1x USB 3.0
Dimensions: 130x217x60mm
Weight: 2.9kg

LaCie Rugged Mini

LaCie Rugged Mini
  • RRP: £107, US$109.99

LaCie's range of Rugged drives have been around for more than ten years, but they're still going strong. The Rugged Mini offers up to 4TB of storage in a pocket-sized design that is even smaller and tougher than ever before.

It has a distinctive orange rubber sleeve inspired by the design of the Spectrum Pursuit Vehicle (SPV) in the old Gerry Anderson series, Captain Scarlet, and is just 19mm thick for the 500GB model (the 4TB model is 26mm thick). There are plenty of smaller drives available, of course, but none that are as tough as the Rugged Mini.

It offers digital security too, as LaCie's Private/Public software provides 256-bit encryption and password-protection. There's an eco-mode that reduces power-consumption by around 40 percent when the drive is connected to your laptop but not being used to transfer data.

The Rugged Mini uses a USB 3.0 interface and a conventional hard drive mechanism, so it won't be as fast as the latest solid-state drives with a Thunderbolt interface. However, it's a lot cheaper than SSD drives and as tough as old boots if you need to keep your data safe when you’re on the move.

Connectivity: USB 3.0
Dimensions: 500GB - 19x86x135mm
Weight: 500GB - 260g

Seagate Seven

Seagate Seven
  • RRP: £89.99

Seagate's super-slim Seagate Seven is claimed to be the smallest 500GB hard drive in the world.

We'd be hard pushed to find fault with that claim since, as the name implies, this super-slimline portable drive measures just 7mm thick and weighs a mere 178g. You can easily slip it onto a jacket pocket, or into a case alongside your MacBook and hardly even notice it's there.

And despite its compact design, the Seven is also very sturdy. It's housed in a stainless steel case that looks very smart and makes a great match for Apple's MacBook laptops, but is also strong enough to cope with a few bumps in a backpack when you're out and about. The drive also includes Seagate's Dashboard software for making backup copies of photos that you upload on to social sites such as Facebook.

Our only real complaint is that there's only one version of the Seven drive currently available, with just 500GB storage. If you need more than 500GB then you'll have to stick with the Slim Portable drive, which offers up to 2TB, or one of the many rival drives available from other manufacturers.

Connectivity: USB 3.0
Dimensions: 7x82x123mm
Weight: 178g

WD My Book Thunderbolt Duo

WD My Book Thunderbolt Duo
  • RRP: £399

The Thunderbolt Duo has been around for a while, but it's still a really good option if you simply need a big fat hard drive that can store stacks and stacks of photos and other data.

The chunky Thunderbolt Duo is a dual-bay drive that starts with a minimum of 4TB storage for a little under £400, and goes right up to 8TB for a really competitive £420. The two internal drives are removable too, so you can add extra storage simply by swapping in new drives whenever you need to.

You can use the Thunderbolt Duo as a conventional hard drive, but it also supports RAID 0 (for speed) and RAID 1 (for security), which makes it a good choice for photographers who need strong performance and security for their work files. The drive also works with Time Machine for automatic backups, and provides password protection and encryption for added security.

The drive still uses Thunderbolt 1.0, rather than 2.0, but its low cost means that the conventional hard drives used here wouldn't really benefit from Thunderbolt 2.0 anyway. If you do need even more storage and stronger performance then there's a My Book Pro model also available that does offer Thunderbolt 2.0 and up to 12TB of storage. 

Connectivity: Thunderbolt 1.0
Dimensions: 99x157x165mm
Weight: 2.3kg