Whenever I try to initialize a LanguageModelSession (let session = LanguageModelSession()), my app crashes with EXC_BAD_ACCESS. SystemLanguageModel.default.availability returns available. I tried running the two sample projects I found that use Foundation Models, FoundationModelsTripPlanner and SwiftTranscriptionSampleApp, and they both also crash—immediately on launch. I commented out the Foundation Models logic from the SwiftTranscriptionSampleApp and ran it again, and it no longer crashed. I'm on macOS 26 Beta 4 on an M1 Pro device. I'm based in Austria (EU), if that matters.

I see a chunk load error in the browser console. I already reported this: FB17664487

To reproduce: In Xcode, create a new project with SwiftData storage Add a new item in the preview — everything works fine so far Enable CloudKit sync for the target (add iCloud capability, check CloudKit, add a container) Go back to the preview and add a new item — Xcode will now freeze As soon as you modify the SwiftData storage, the preview freezes and the Xcode app becomes extremely slow until you either refresh the preview or restart Xcode.