See https://stackoverflow.com/questions/4494028/warning-msb8012-make-sure-that-outdir-targetname-and-targetext-prope?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa for the gory details. This error is not just a project upgraders error. It can also happen when moving projects - as I found after recreating the projects afresh and still having the error. The essential problem is that the configuration parameters are over determined, and hence can conflict. It's compounded by there being no warning of conflicting parameters at project configuration time.
The project files move from lib-src into the win/Projects folder. Intermediate files are now kept well away from the files we want. Less use of '..' and more of $(SolutionPath) in paths.
