Hi Leonard, thanks for reporting these problems, I have not heard of them before. That's unfortunately going to be difficult to track down the bug when it happens only after a long period of use like that.

If at some point in the future you notice that it tends to occur after some specific action or using one particular tool please let me know about that since that could make it easier for me to reproduce over here. It's very difficult to fix problems that I am not able to reproduce over here with some specific series of actions.

Your #3 can probably be corrected by setting the file association for .3dm files to make it open MoI rather than opening TextEdit.app. See here for an overview on how to set what application will open when you double click on a particular type of file:
http://osxdaily.com/2013/08/08/change-default-application-open-files-mac-os-x/

- Michael