IOS Storyboards Do Not Support Target Device Type "Watch"

In addition to target memberships, and especially when working with a single target that supports multiple platforms (ex. iOS and tvOS), you can more-deeply customize the build by clicking on the project in the sidebar then going into the target, selecting "Build Phases" and then using the "Filters" column.

By default, files are listed as "Always Used", but you can limit to specific platforms as needed in this way, even as part of a single target.

It would be nice if these same settings were exposed in the inspector as well since this feels pretty hidden, but this is how it is as of Xcode 14.1 at least.

I just crossed the same problem. I did:

1. Click on the warning
2. On the right side select the "File Inspector"
3. Go down to the "Target Membership"
4. Unselect the "main app"

This worked for me. Cheers.