Nope, no crash report, no popups or warnings. 3DCoat closes on "Help > upload mesh to sketchfab.com" click and that's it.
Ok. I'll try to contact support. Thank you anyway.
I have uninstalled the 4.8.20 version, downloaded and installed the 4.8.22 version, and the problem is the same...
Can there be a browser problem? I use Opera as a default, maybe 3dCoat just can't start it and crashes?