Just a suggestion.Yes, ADE has the correct paths to the configs, SDK and to the content root folder, which on my machine is a custom location: “E:\Content” and which contains Community and OneStore.
Alpha 14 was working with Navigraph present, but it has been a while since I last used it, and I uninstalled it before installing Alpha 18.
The. Navigraph installer does modify Content.xml so that its files are layered correctly in the overall scenery system, so perhaps that is what is causing the issue.
With Navigraph present, ADE will throw the error message about “Base file missing” when creating a new project using a stock airport. Merely running the Navigraph uninstaller will allow ADE to create new stock projects with no errors.
It’s not a major problem. I was curious though if you had received other reports of this problem.
Set the properties of your MSFS folder to "not hidden" and not "Read Only" and run ADE as Administrator.