Xcode 14 – Storyboard Preview/IBAgent-iOS shows black screen (iOS 16.2 Built-in)

I’m using Xcode 14.2 on macOS 12.7.6.

When I try to open the Storyboard Preview or run IBAgent-iOS, I only get a black screen.

The log shows an error like this:

Encountered an error communicating with IBAgent-iOS.Failed to spawn IBAgent-iOS on iPhone 14 (iOS 16.2, Booting)Process spawn via launchd failed because device is not booted.Bad or unknown session: com.apple.CoreSimulator.SimDevice...

I tried deleting and recreating simulators, but the issue persisted with the iOS 16.2 Built-in runtime.

How can I fix this?

Answer:

This happens because the iOS 16.2 Built-in runtime that ships with Xcode was corrupted/incomplete.
Even if you recreate the simulators, IBAgent-iOS cannot boot the device, which causes the black screen in Storyboard Preview.

The fix was to install a clean runtime.

Steps that worked:

1. Open Xcode → Settings → Platforms.

2. Click + and install another runtime, e.g. iOS 16.0 Simulator (or 16.4/17.0 if available).

3. Restart Xcode and then start it again. Now be happy.

Explanation (why this happens)

1. The iOS 16.2 Built-in runtime is bundled inside Xcode and cannot be removed.

2. If it becomes corrupted (CoreSimulator data issue), IBAgent-iOS fails to boot and Storyboard Preview shows only black.

3. Installing another runtime provides a fresh, working copy of the simulator, which fixes the issue.