during autosave, max will close when clicking to close the VFB - as soon as the autosave is complete, max shuts down.
luckily the autosave completes ok, so the file is recoverable from the autoback.
vray 3.50.04 - max2017
May you try with the latest 3.60.03 and see if the same thing happens?
Just seen 3.60.04 is out!
Have you updated to 3.60.04 and is the issue still present there (I couldn’t reproduce it on our end)?