I like to pride myself on being a relatively well-versed Mac user. Obviously there are niches where I don’t know as much, but overall I feel like I know about the Mac pretty thoroughly. Something I only learned about recently after going through the Apple Device Support Certification (expect a video and article on that later) is the Content Cache sharing option.

What is Content Caching?

Content Caching is a feature first released in Mac OS 10.13 “High Sierra” and useful for households and other environments where you have a lot of Apple devices. When enabled, it allows your Mac to act kind of like and Apple update server, for your household, a particular network, sub-network, or select set of IP addresses. Meaning that when Apple releases one of its mass updates, be it a brand new upgrade or just a monthly security patch, the Mac will get those updates from Apple for all your devices. Then when your other Apple devices go to get those updates, they will automatically get them from your Mac.

This has 2 benefits. The first being most networks typically have faster speeds moving things within the same household than with getting stuff from the public web. The second is this can save on some bandwidth whether you think data caps or just limited speeds. If you have a household with multiple iPhones, normally each iPhone would have to download the same security patch from the web, meaning you’re downloading 4x as many MB or GB as the size of the update. However if a content caching Mac can download it once, and all those iPhones will just get it from the Mac instead. One update for all as the case may be.

As you may have guessed from the last paragraph, content caching stores updates for multiple Apple platforms. Specifically it can store updates for iPhones, iPads, Apple TV, Apple Watches, and Mac computers to be shared across your network (sorry HomePod). It can even store other public resources such as updates to App Store apps, Apple TV Screensavers, Apple Books content, and more. Of course they have to be on the same network or sub-network. If you update your iPhone in a hotel away from the content caching Mac, it’s not going to help you.

There is also a personal option to have it store some iCloud data for quicker access for devices on the same account and network. The aforementioned Apple Books as well as apps tied to your iCloud account, but it can also cache photos, documents, and schoolwork data so your other devices can more quickly. If you’re the only one in the home or you share Apple content with those in your household, then it may be worth enabling this. If you’re worried about privacy concerns, note that Apple doesn’t let you see what’s been stored in the cache or is being served on it at any time. But your IP address and region is registered with Apple to ensure you get the proper content both for technical purposes but also to follow your regions legal obligations.

Enabling Content Caching

If you’re using OS 13 Ventura or later, open the Settings app, go to the General section in the left sidebar, then “Sharing” on the right side. You’ll see the section labeled “Content Caching” currently turned off. If you hit the little information “i” to the right of the section, next to the on switch, you’ll see get some additional options. Here you can set things such as whether to allow only Shared Content sharing (updates, screensaveers, etc.), only iCloud content, or both. You can also check a box to enable this Mac’s cached and internet connection to be shared with iDevices connected via USB to this Mac, adding an additional way to benefit from the cache. Lastly, you can set a maximum size to the cache by clicking the “Options” button and setting the value there, then hitting the OK button. This will also tell you how much space is being used by the cache and how much of it is iCloud vs non-iCloud data (if you’re caching both).

If you’re using a OS 12 Monterey or earlier, you’ll open the System Preferences app and then go to the “Sharing” section. The Content Caching section will be at the bottom of the left sidebar. Clicking the section will change the right side to show you your options (though you may have to unlock the panel). Hitting the “Options” Button will allow you to adjust the amount of space the cache uses. Check the “Content Caching” box in the left sidebar to enable it when you’re ready.

It’s worth noting that it may take a couple minutes between when you first turn on the caching service and when it is fully operational.

Checking The Cache

If you want to check how much space you’re using you or how it’s being utilized, you can check these things out in the Activity Monitor. Once Content Caching is enabled, you’ll get a new tab at the top of the Activity Monitor appropriately labeled “Cache” that you can use to see the things like amount of data being served, dropped, released, shared among other Mac caches, etc.

As far as settings go, there aren’t many you need to deal with beyond what is in the Settings app if you’re just managing a basic home network. But if you want to learn about them or are managing a bigger network, I’ll actually direct you to another site called The Eclectic Light Company that has more details about editing them through the plist and what you can expect.

Things to be Aware of

If you enable Content Caching, some other things might not work quite right.

You won’t be able to enable Internet sharing on the Mac. In order to turn this Sharing feature back on, you’ll have to temporarily disable Content Caching.

You also won’t be able to download previous versions of Mac OS via the Terminal, which I wrote a guide to over here.