Microsoft Flight Simulator loads an add-on only when the add-on folder is directly in your Community folder. If the add-on folder is inside a second folder with the same name (a "nested" folder), the simulator does not find the add-on and starts without it.
To prevent this problem, use Simstaller to install your add-ons.
How to find a nested folder
A correct add-on folder contains the files layout.json and manifest.json.
-
Incorrect:
Community\p42-imm-simfx\p42-imm-simfx\layout.json -
Correct:
Community\p42-imm-simfx\layout.json
Example with SimFX: open your Community folder, then open the p42-imm-simfx folder. If it contains only one more folder named p42-imm-simfx and no layout.json file, the add-on is nested.
How to fix a nested folder
- Close Microsoft Flight Simulator.
- In File Explorer, open your Community folder.
- Open the outer add-on folder (for example,
p42-imm-simfx). Then open the inner folder that has the same name. - Press Ctrl+A to select all folders and files. Then press Ctrl+X to cut them.
- Go back one level, to the outer add-on folder. Right-click an empty area and select Paste, or press Ctrl+V.
- Delete the inner folder. It is now empty.
- Make sure that the outer add-on folder now contains
layout.json,manifest.json, and the other add-on folders. - Start the simulator.