How to choose an external hard drive for macOS Time Machine backups – TechRepublic | Hot Mobile Press

Time Machine backups are a reliable option for backing up your Mac. But which hard drives should you pair with macOS’s built-in backup app? How to choose the best backup disk for your needs.

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Time Machine is a proven backup solution for macOS. The only catches are that you need a hard drive or two and remember to physically connect an external hard drive to your Mac. I have found that using a docking station both at work and at home has solved these problems.

But which external hard drive should you use to collect the Time Machine backups? While there are numerous options, some will work better than others depending on your preferences. How to choose the best external hard drive for Time Machine backups.

How to choose an external hard drive for macOS Time Machine backups

form factor

One of the first questions to answer is whether you need a full-size external hard drive that requires its own power source. An example of such an option, sometimes referred to as a desktop drive, is SanDisk’s G-DRIVE.

However, in my experience, external drives that require their own independent power source fall out of favor. Instead, portable offerings like Western Digital’s My Passport for Mac (Figure A) and the Seagate Basic portable drive are growing in popularity, in part due to their flexibility and portability.

Figure A

Western Digital’s My Passport for Mac is an inexpensive external hard drive that’s good for collecting Time Machine backups.


Another question to be answered is the storage capacity of the external hard drive. While 1 TB used to prove plenty for accumulating a long history of Time Machine backups, some new Macs are shipping with drives that large onboard.

A good rule of thumb is to buy an external backup drive that’s at least three times the size of the Mac’s own hard drive. If your Mac uses a 256GB SSD, a 1TB external drive should work fine to collect Time Machine backups. However, if your Mac uses a 1TB drive, you should consider buying a 3TB or 4TB external hard drive. Thankfully, prices have come down to the point where a reliable 4TB hard drive can typically be had for around $150.

connection method

Before you buy an external hard drive for collecting Time Machine backups, be sure to check how you usually work. If your typical work day involves connecting a power cord and an external monitor to your Mac, and your Mac only has two Thunderbolt/USB-C ports, you’ll need a dock or hub like Twelve South’s StayGo USB-C Hub in Consider or Brydges Stone C model.

Or maybe your Mac has an available Thunderbolt/USB-C port, or you’re using a third-party dock with traditional USB-A ports. If you’re buying an external hard drive to store Time Machine backups, first make sure the drive has the connectivity option you need. If you have a choice, consider switching to Thunderbolt/USB-C, as the standard offers faster data throughput and can speed up backup completion times.


While some drives come in the form of thin, sleek cases – the LaCie Mobile Drive is one such example – that offer minimal protection from drops, bumps and vibrations common when traveling, others are more suited to rugged use. LaCie Rugged Portable Hard Drive (Figure B) is one such example, and one I’ve personally found over the years works well in this area.

Figure B

The LaCie Rugged Portable Hard Drive is available with different storage capacities, has a rubberized housing and is designed for mobile use.

Consider your needs, then explore the variety of offerings available. Just be sure to consider the benefits of a rugged or rubberized case, which can help extend the life of the drive if you want the hard drive to prove extremely portable.


External hard drive performance affects how quickly Time Machine backups can be completed. Several factors come into play, including the hard drive type and Mac speed. For example, SSDs on newer MacBook Pros with faster M2 chips and powerful backplanes automatically have an advantage over an older iMac with a traditional 5400 RPM hard drive.

But the type of external hard drive and its connection method also affect the backup time. An external SSD drive works faster than a conventional 5400 rpm hard drive. And as previously mentioned, Thunderbolt connections are typically capable of transferring data faster than legacy USB-A connections.

Buy from trusted vendors

Once you have made your decision, be sure to buy from a trusted vendor. I recommend refraining from buying used external hard drives and not trusting every online seller. Instead, consider purchasing external hard drives directly from Apple or the respective hardware manufacturer.

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