I had Xcode 16 Beta 1 installed and working.
Installed Xcode 16 beta 2 (16A5171r) and now it is unable to download the simulator for that version.
Downloading iOS 18.0 Simulator (22A5297f): Preparing to download...2024-06-25 14:21:27.456 xcodebuild[88553:5158819] DVTDownloadable: Download Failed. Downloadable: { authentication = none; category = simulator; contentType = cryptexDiskImage; dictionaryVersion = 2; downloadMethod = mobileAsset; fileSize = 8254433558; identifier = "com.apple.dmg.iPhoneSimulatorSDK18_0_b2"; isInternalContent = 0; isUserInitiated = 1; name = "iOS 18.0 Simulator (22A5297f)"; platform = "com.apple.platform.iphoneos"; simulatorVersion = { buildUpdate = 22A5297f; version = "18.0"; }; version = "18.0.0.2"; }. Download failed. Downloading iOS 18.0 Simulator (22A5297f): Error: Error Domain=DVTDownloadableErrorDomain Code=41 "Download failed." UserInfo={NSLocalizedDescription=Download failed., NSUnderlyingError=0x600001f075c0 {Error Domain=DVTDownloadsUtilitiesErrorDomain Code=-1 "Failed fetching catalog for assetType (com.apple.MobileAsset.iOSSimulatorRuntime), serverParameters ({ RequestedBuild = 22A5297f; })" UserInfo={NSLocalizedDescription=Failed fetching catalog for assetType (com.apple.MobileAsset.iOSSimulatorRuntime), serverParameters ({ RequestedBuild = 22A5297f; }), NSUnderlyingError=0x6000031fe3a0 {Error Domain=com.apple.MobileAssetError.Download Code=18 "Download from live asset server could not get an asset matching the requested one. (Catalog download for com.apple.MobileAsset.iOSSimulatorRuntime)" UserInfo={tryAgainLater=true, NSLocalizedDescription=Download from live asset server could not get an asset matching the requested one. (Catalog download for com.apple.MobileAsset.iOSSimulatorRuntime), pallasNoPMVMatchFound=true}}}}}