I tried running the command as you recommended: xcodebuild -downloadPlatform iOS But the error was: {Error Domain=com.apple.MobileAssetError.Download Code=49 "Download failed due to a bad URL. (Catalog download for com.apple.MobileAsset.iOSSimulatorRuntime)" Following the steps from the page you sent, both resulted in the same error. From what I can tell, it's failing to locate the official runtime version URL.