Hi! I'm justgettiodng into AR and got into this problem with a cause and a solution.
Everything was working (kinda), exporting models from modo and importing to RConverter. USDZ sometimes works, sometimes I got the pink stripped materials (not sure why or how to fix), others times gltf format.
CAUSE (for me at least): I installed Gestaltor to try it out as a gltf editor (looks nice) and then the problem started: every gltf I had changed it's icon to Gestaltor's file and Reality Converter stopped recognizing them either as drag and drop nor import file.
SOLUTION: I uninstalled Gestaltor (maybe not necessary but cleaner anyway), and then getting File Info on a file and selected "Open with" -> Other -> "All apps" from the dropdown -> Reality Converter. Now it worked!
Hope this helps someone.
V
The same issue just happened to me. Reality Converter suddenly stopped accepting .gltf files. I tried to remove and reinstall the application but it does not solve the problem.
Did you ever get it to work?
I'm having the same problem since the last OS update to Monterey. I'm currently on version 12.0.1 with my Macbook 2020 M1. RealityConverter version is 1.0 (30.3).