Do not attempt to create a new project over an existing directory in Mix-ide. It will wipe the directory leaving no trace. Not even my data recovery tools can see any trace of the directory or files on disk. For whatever reason, Mix started failing and corrupted my .mix file. I attempted to regenerate on by creating a new project over the top of the old on.
It's just lost me a month's worth of work and research.
Bug can be reproduced by (windows 10)...
Open mix and create a New Project
as normal -> folder and files are created.
Create a New Project
again over the same directory -> folder and files are wiped without trace. No new project exists.