Aircraft Simobject - 'Load in Editor' greyed out

Title says it all. I have the latest SDK 0.24.3 and latest MSFS version I created a new Project using the SDK and single engine propeller aircraft Template. I am actually creating a car - MG Midget J2 - and have edited files to suit. I have created the model using Blender and exported it, externals and internals. I have checked all my simobject files line by line against the sim docs including model .xmls. I have omitted all Legacy entries except those that still say Yes under ‘required’. I have double checked my folder locations in the Project Editor and the project file names. I am at a loss to understand why ‘Load in Editor’ is greyed out. Does anyone have any idea what might be causing this?

Did you follow the steps suggested in the docu?

(Build the package, load the aircraft for a flight, open the aircraft editor alternatively to the load in editor?)

Hi, thank you for the quick reply. I followed the SDK doc instructions for creating a new project based on the sample propeller aircraft. I idid not build and fly it as I wanted to change it. I spent much time editing the entries, in fact I did it directly in the .cfg files because the doc descriptions/entries were quite name-specific and easy for me to find in the cfg files and understand. I removed Legacies where not required and added in anything that was missing (actually I don’t think there were any). I can open the Project for editing in Aircraft Editor under Tools but can’t in the Inspector with the ‘Load in Editor’ button which is greyed out. I did check that with another aircraft I made and it works ok there. I’m hoping someone with a more intimate knowledge will be able to help (actually I have seen your name around a fair bit!).

I should have said, of course, that the model doesn’t appear in My Hangar.