Please visit this thread, which has the solution. Could be Xcode failed to download the update follow steps here. https://developer.apple.com/forums/thread/847137

Thank you for your thoughtful response.

Let's say I have IF AVAILABLE, are these statements ignored if I were to submit? My idea is to submit build that supports iPhone resizability horizontal/Vertical size class and mirroring resizability support (iOS 27), while improving upon final release build for Duo up until support is enabled. Working around the clock here.

FEEDBACK NUMBER: FB24912030

You need one more step to complete this. Xcode 27.1->Open Developer Tool->Device Hub Press + then iPhone Then Make sure 27.1 OS Version 27.1 is selected Duo appears Press Create. Should fix it for you.

This worked for me. Thank you. Accepted answer.

Yes, I saw the release about 5 minutes after they posted it. Do you know how to get Device Hub and 27.1 showing the Duo sim? Thanks!!!

Nevermind. It looks like you just released 27.1 + iPhone Duo sim a few minutes after this message. Thank you.

Thank you for your response as its really helpful. I'm currently re-architecting my custom user interface and testing using iPhone Mirroring for resizability and future iPhone Duo support.

Thank you!

Thank you. I was doing 5 different things at the same time including using onAppear conditional display and also setting navigationbackbutton. This was causing race conditions and somehow duplicated toolbar item rendering when process completed. I am unable to recreate. I do not believe this will cause issues for other developers as I'm doing something very complex with overlays appearing above the toolbar which is hidden while overlay is active.

Same issue. Apple Engineers please fix. How are we supposed to develop using Foundation Models Framework on our Macs without possibly corrupting our system and main machine. is there a workaround?

Same issue for me. Running high powered Mac Pro max memory and GPUs Sequoia 15.5.