You know the cliché, “bigger is better”? That almost always applies to a device’s storage capacity. It definitely applies to Apple’s Macs, which, at the lower-priced standard configurations, are mostly all set at 256GB. That’s too small, even if you’re not a professional who deals with large files. We recommend getting at least a 512GB SSD, and here at Macworld, we were recently reminded of how small 256GB is.
A Macworld editor (who shall remain nameless, but here are only five of us) has the unfortunate burden of a 256GB SSD in their Mac. (Okay, yeah, “Practice what you preach, Macworld.” I’ll be sure to tell upper management.) And they had problems because an extremely large amount of space (108GB) unexpectedly became dedicated to System Data–that took up half of the 256GB SSD.
Foundry
Now, you’re probably looking at the screenshot above and thinking, “Dang, you need to do something about Messages and Photos” and sure, you’re right (they assure us that they have Messages in iCloud and iCloud Photos set up). But when macOS and System Data take up 129GB of space on a 256GB SSD, that’s a lot. Something odd happened with System Data. Eventually, enough space was freed to install the recently released macOS 15.4 update. Installing the update resulted in a smaller System Data allocation of just 45.75GB and over 70GB of newfound free space.
If you’ve never heard of “System Data,” that’s because you’re not really supposed to be preoccupied with what it is. macOS is supposed to manage it for you, and even if you do want to manually manage it, it’s no trivial task and is probably best done with the help of a disk cleanup utility. Regardless of whether you manage System Data or not, something happened with the OS that caused a 256GB SSD to run out of space temporarily. That could be catastrophic if, say, you’re working on your kid’s birthday video in iMovie and you suddenly find out that you can’t save anything.
This particular situation might not be common, but it exemplifies why 256GB is too small for a Mac’s primary storage device. Stuff happens with the OS that takes up space and you can suddenly find yourself with a full drive. You can put in the work to manage the space so you don’t trap yourself, but honestly, do you really want to do that? There are just too many other factors that come into play, too. To expand on the iMovie example I mentioned earlier, there’s an old rule of thumb that says a device should have 25GB free for iMovie (or other movie projects). And 25GB is 10 percent of a 256GB SSD’s space. That’s a lot.
When we polled three other Macworld editors, they had System Data at 55GB, 68GB, and 87GB. Thankfully, those editors have 1TB SSDs, so there is no issue with free space. Nothing to worry about, even if System Data has to balloon up temporarily. The point is, until Apple increases the base level to 512GB, do yourself a favor when you buy a Mac and get an SSD bigger than 256GB. It will save you from future headaches. And if you already have a 256GB drive, consider one of these ways to expand your Mac’s storage.
