Simple myapp won't build

[ScruffR]

Not an answer to your question, but have you heard about Particle Workbench (based on VSCode) which will be the new desktop IDE that also deals with all the download and setup tasks required to build Device OS and Application offline?

Feature Overview of Particle Workbench

At Spectra, our first conference for developers and product creators, we hosted a workshop that gave an overview of the features currently available in Particle Workbench. The workshop was recorded and will be posted soon. In the meantime, here’s some of the key features we highlighted. Command Palette If you’re new to Visual Studio Code, the Command Palette will become a familiar part of the user interface. As the name implies, the Command Palette provides access to many commands such as open …

I've managed to setup Eclipse to build Device OS in the past, but switching target versions with it was just a PITA, but with PWB that's become a simple task of changing one switch and let the IDE do the rest.