Hi. Today we upgraded to Xcode 27 and installed the iOS 27 runtime component. Now storyboards cannot be opened. Xcode only displays "Loading iOS 27.0..." Besides, we cannot create simulators either. iOS 27 runtime appears missing even though it is installed.
We tried removing and reinstalling the runtime but it didn't work. Right now all development came to a halt. Please help.
Thanks for the post.
Are you opening a project created from another older version of Xcode? Do you know what version? When you create a new project with Xcode 27 release with Storyboards, do you get the same issue?
Any chance to isolate that storyboard into a focused project so we can see what is wrong opening that Storyboard? Do you know what version of Xcode that storyboard was created? Any errors or warnings in the console?
Have you tried to relaunch Xcode after killing the simulator? Have you run it on a real device? Open Terminal and run the following command to terminate the stuck service:
sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
Launch Xcode again and check if you can create a simulator or open a Storyboard.
Let me know if you can provide that Storyboard in a simple focus project and we can go a file a bug?
Albert WWDR
Hi. I tried both creating a clean new project and opening an old one created from the previous Xcode version.
Actually both simulator and storyboard issues seem to stem from the same point: ios 27 platform component cannot be detected even though it is installed.
Attached is a storyboard created in version 27.
BTW killing CoreSimulatorService did not work.
Weird enough, the project compiles and runs on a physical iphone.
I had a very similar issue after upgrading to macOS 27.0 / Xcode 27.0 on an Apple Silicon Mac.
Opening Storyboards/XIBs made Xcode extremely slow or completely unresponsive. I was also able to reproduce it with a brand-new Xcode project, so it wasn't related to my project's dependencies or code.
What eventually made Xcode usable again was resetting Interface Builder's simulator data and reinstalling the iOS 27 Simulator Runtime.
I closed Xcode and moved the Interface Builder support directory:
~/Library/Developer/Xcode/UserData/IB Support
to a backup location, then removed and reinstalled the iOS 27 Simulator Runtime from Xcode Settings → Components.
After that, the first Storyboard load was still somewhat slow (~20 seconds), and Interface Builder initially used quite a lot of CPU while its private simulators initialized, but after that XIBs/Storyboards became usable again.
I've since rebooted the Mac several times and tested multiple projects, Storyboards and XIBs, and the severe hangs haven't returned.
I would keep a backup of the "IB Support" directory instead of deleting it initially.
