How to install App Store apps onto SSD drives using macOS Sequoia

Did you know that Apple’s macOS 15.1 Sequoia now lets you install and use applications acquired from the Mac App Store directly onto an external drive? This enhancement is actually particularly useful if your workflow requires you to handle a space-devouring application.

Here’s what you need to know about it and how it works.

What’s changed?

While anyone who is paying attention should already be impressed by the sheer speed and performance of Apple’s new Macs, that performance also means pro users will push the platform to its limits, banging into any inherent challenges to how Macs work.

One of these challenges is the need to optimize the space you have on your Mac when running larger applications — and given the cost of installing additional space on most Apple hardware, there was demand for a lower-cost way to do just that. The solution comes with macOS Sequoia 15.1.

Wait, is this really new?

So you’ve spotted that many Mac apps (downloaded from outside the App Store) allow users to install and use them on external drives. This is not automatically the case for applications downloaded and installed from the Mac App Store,however — these insist on being hosted on the Mac’s own drive. You have always been able to run most apps and macOS from an external drive, but now you can do the same with App Store apps, including Pro Apple apps.

What are the limitations?

There are some limits to the new feature tweak. 

• The biggest is that you’ll only be able to install applications larger than 1GB in size, which is great for games and pro apps, less great for users of smaller apps, who may just want to manage storage their own way. We can hope Apple lifts the 1GB restriction eventually.
• The second limitation is the speed of the external SSD; obviously, the speedier it is, the better the offloaded application will perform.
• The final — and most inconvenient — limitation is that once it is enabled it is not optional. In the future, you’ll need to install any application of 1GB or more on external storage unless you turn the setting off. 

What do you need?

You need to be running macOS 15.1 and have a suitable connected drive. The drive must also be formatted to APFS. To check that this is so, with the drive connected to your Mac, right-click the drive icon in Finder and select “Get Info.”

How to begin installing Mac apps on external drives

Before you use the feature, you need to open the Mac App Store on your Mac.

• Go to App Store>Settings in the Menu bar.
• Check the box beside the “Download and install large apps to a separate disk” item in Settings.
• When you have enabled that setting, you can select the external drive you want to save your applications to.

After that, when you want to install a large application from the Mac App Store, you will need to ensure the external SSD you want to use is connected to your computer.

How to use a Mac app on an external drive

At the risk of sounding obvious, you do need to connect the drive your application is stored on to your Mac to use the application you have hosted there. It is relatively seamless after that — the app will be visible in your Applications folder, opens with a double click and can be used just like any other app. (One thing it does not do is appear in Launchpad.)

Why does it matter?

Cost is the biggest reason this is important. Additional storage in Macs isn’t cheap; it will cost you an additional $600 to slot 2TB of storage inside the base model MacBook Pro, while a good and speedy external SSD should cost you around two-thirds of that, or less if you’re a little more flexible. That cost increases if you are provisioning multiple seats, so in some cases this feature could help you stretch purchasing budgets a little further. Consumer users can also use this to enable them to better explore and learn about professional applications without needing to worry about having enough space on their Mac.

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