Inventor leaves many ways open to a user to screw himself up. Perhaps, we should have Inventor do a better job of handholding us?
Example: Inventor allows you to rename a file that is currently open from within it's own dialogs. The result is this error message:
I knew better, but wanted to see what would happen. Inventor is now so upset with me, that I can't even close this file. I was about to kill the Inventor.exe process, but figured out a workaround. I made a change to dirty the file so that Inventor would prompt for a save, clicking no allows for closing the file.
Improving the way Inventor handles these sorts of problems would make for a much better experience for new or casual Inventor users.