What to do when your Mac’s internal storage runs out

Once upon a time, Apple made it easy to crack open a Mac, remove a hard drive, and replace it with a new one when the old drive was no longer working, too slow, or of insufficient capacity. Those days are long gone for most Macs, leaving readers to wonder what the best path forward is.

You have effectively three options:

Check iFixIt and other online guides to see how difficult it is to replace an internal drive. Depending on the model, it may be relatively easy for Macs released through 2014. For instance, a 2014 MacBook Pro requires just unscrewing the back case, unscrewing the SSD, and replacing it with an Apple-compatible SSD.Consider hiring a shop to upgrade your drive. For some Macs released in the 2010s, especially iMacs, an upgrade or replacement requires removing and reinstalling a lot of screws, cables, and seals. Of course, consider labor costs: it could cost $150 to $250 just to open up and close the computer.Add an external drive via FireWire 800, USB 3, or Thunderbolt 2 or 3 (or even 4).The last option is the most straightforward and works with any Mac. While I’m stretching back years when I bring up FireWire 800, if that’s the fastest connection on your Mac, it’s a better choice than USB 2.0 (800Mbps versus 480Mbps). (However, note that if your Mac has FireWire 800 and not USB 3 and it isn’t an iMac, it likely has an easy drive replacement option.)

External SSDs up to 1TB and external hard disk drives (HDDs) of many terabytes have dropped to highly affordable prices. Match the drive to the interface you have: there’s no sense in buying a high-performance SSD that can deliver 2 GBps (18Gbps) and plugging it into USB 3.0, which maxes out at 625MBps (5Gbps). However, if you have a computer new enough to have a Thunderbolt 2 (20Gbps) or 3 or 4 (40Gbps) interface, you can opt for a superfast SSD if that fits your budget and needs.

I upgraded my 2017 Intel iMac to a 1TB Thunderbolt 3 SSD in 2020, dramatically improving its performance. The iMac died abruptly (at nearly five years old) in 2021, and I opted to shift to an M1 Mac mini. Rather than pay the premium for Apple’s 1TB internal drive on that model, I bought one with 16GB of RAM and a 256GB SSD, then migrated my iMac’s system to the external drive via a Thunderbolt 4 connection.

Later, I realized my Photos library was too slow on an external HDD. (I have two external 8TB HDDs for Time Machine backups and media storage.) To improve performance, I migrated my Photos library to an inexpensive 1TB USB 3 SSD, as described in “How to move your Mac’s Photos library to an SSD for better performance.”

You have lots of different options in which you can mix HDDs, slower SSDs, and faster SSDs to find the right mix.

With a laptop, you may find an external drive irritating to manage while traveling, but spending $100 to $300 for an external SSD might avoid a cost after trade-in of hundreds to well over $1,000.

This Mac 911 article is in response to a question submitted by Macworld reader Julie.

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External Hard Drives, Mac