I was getting this error in Chrome after creating a new app and running elm-app start:
Uncaught TypeError: Cannot read property 'embed' of undefined
It appears that due to some name changes, Elm.Main.embed(root, logoPath) should now be Elm.App.embed(root, logoPath): https://github.com/halfzebra/create-elm-app/blob/master/template/src/index.js#L7