Invalid Swift Support / The SwiftSupport folder is empty

when try to export after "Xcode->Product->Archive" you should choose "save for ios app store deployment" option

The same problem confused me a couple of days, the above setting can solve this problem.

no matter "embedded content contains swift code" is yes or no.

important note: this only works for projects that do not use swift, see comment below

I just met the same issue and resolved it by making the following change - If you used to have Swift files in your project but then removed them, you only need to set "Embedded Content Contains Swift Code" to NO in Build Options.