New project not building: Thumbnail.jpg error

I created a new project in the same manner I did before, but when I click
“Build & export” it returns an error " ‘Thumbnail.jpg’ is missing
(‘Thumbnail.jpg’ not found on disk)" I checked and it’s there in all the usual
places. The error message doesn’t say which folder it’s looking at, so I’m
stuck. I reselected the thumbnail in “Summary Content Manager” and it shows
fine there, along with the rest of the data. How I can I see where the
compiler is looking for this file?

This is definitely a bug. I looked at the console and there was another issue
with my SimObject XML (typo), and once I fixed it - this Thumbnail error
disappeared. Because there was no Thumbnail error, and it wasn’t actually
missing. This is sime kind of a bug in error reporting…

I second that. The

Thumbnail.jpg error

appears quite often, without any correlation with the actual Thumbnail.jpg.
file. I have reported that earlier:
https://devsupport.flightsimulator.com/t/3499 .