Installing simulator runtimes from the command line

After installing the Xcode 27 beta, I tried to download all the simulator runtimes that I needed. The watchOS runtime installed flawlessly, but I had issues installing the iOS runtime. I kept seeing a dialog that said that Xcode was fetching download information and no matter how long I waited; that dialog would not go away.

I reinstalled Xcode and rebooted my Mac, but I just could not get the iOS runtime to download. I looked around on the internet, and I found that you can install runtimes from the command line using xcodebuild.

By running xcodebuild -downloadPlatform iOS you can download the runtimes for the specified platform using the Xcode version that you have selected on the command line.

To make sure that you have the correct Xcode version selected, use xcode-select -p to see which Xcode you have selected. If it's not the Xcode version that you want to install runtimes for, use xcode-select -s <path> to choose your Xcode version. For example, xcode-select -s /Applications/Xcode-beta.app. Note that you should run these commands as sudo.

In my case, installing with xcodebuild initally didn't work. I kept seeing the following:

Finding content...
Automatically resolved architecture variant for platform iOS as 'universal'.
No matching downloadable found for platform: iOS
No downloadable was found for iOS.

This told me that xcodebuild was looking for a universal iOS runtime, which it couldn't find. I tried installing watchOS and visionOS through this exact same command, and I saw that those were actually pulling the arm64 runtime instead of a universal runtime.

This made me think that maybe iOS should also be downloaded as arm64.

After a little bit of digging through the documentation, I found that I could run the following command to specify that I wanted to download the arm64 runtime instead of the universal one:

xcodebuild -downloadPlatform iOS -architectureVariant arm64

With this command, I was able to easily install iOS 27 similar runtimes for Xcode builds, so I should run in a similar way, because you are not able to install your runtimes for any other passage runtime from the command line and not directly manage the client installing your runtimes for your Xcode builds. You should also use a single command to install all the different platforms that would work a little bit like this:

xcodebuild -downloadAllPlatforms -architectureVariant arm64