Although I am one of the group of no crashes with Sonar, since X1, track heavy (with a lot of midi) projects would sometimes hang while loading forcing me to do a reboot because the midi activity icon will not release or close.
I could never find a consistent recipe to cause the projects to hang (all soft synth/midi tracks are frozen) so I never filed a problem report.
On a lark, I decided to turn off Prefs>Customization>Display>"Show MIDI Activity on Windows Taskbar".
Six days later, I have not had a project hang on load (highly unusual for me) and the projects are possibly opening a little faster.
Just wanted to pass this tip on and I have posted in the Problem Reports forum that there may be an issue with the activity icon enabled.