This bundle is invalid - Your archive contains paths that are not allowed: ( "AppThinning.plist" )

Question

We made an archive with Xcode 9.
We exported this archive with Xcode 9.
We successfully uploaded the app to iTunes Connect with Application Loader. Yet, soon after, we got this message:

This bundle is invalid - Your archive contains paths that are not allowed: ( "AppThinning.plist" )

This was not happening with Xcode 8.

Answer 1

When you're exporting with Xcode 9 or later, they will ask you if you want to Strip Swift symbols:

Well, don't uncheck it! And the error will be gone.