I've had the same problem since I started working with C2, the program freezes upon trying to close it, then I have to CTRL-ALT-DELETE it and then it doesn't respond. Almost never closes properly, happened regularily both on R132 Free and Personnal license, and R139 in Personnal License. I'm on Windows 7.
I also get a bunch of crashes in general, seemingly at random, so I have to save often. Maybe it's all related to the size of the file? My project has 583 Events, it's Approx. download is 34.6 MB and it's memory use is 136.7 MB.
Anyhow, I really hope this is improved sometime, the program not closing is kind of annoying, but the recurrent crashes are sometimes very upsetting; sometimes it seemed like the Ctrl+S command actually prompted the crash (not very convenient lol).
Anyways, good luck with all this hard work, thanks so much for the great program!