I installed Carenado B350i into the Airplane folder. I'm thinking now that was probably wrong. Carenado install app doesn't show the proper directory for FSX-Steam, so I just guessed. FSX isn't working now. I'm going to uninstall the add-on if I can, and try again, installing into C:\Programs (X86)\steam\steamapps\common\fsx. Does that sound right?