For anybody having problems with Vegas Pro 12 -- constant crashing, other bugs, etc -- I'd urge you to contact Sony support: https://www.custcenter.com/app/ask. Give them all the specifics you can to hopefully make their job a little easier in ironing out some issues.
It's frustrating to me to have Vegas crash all the time (for me, I'm thinking it might be related to my P2 MXF videos), but I figure the more useful info Sony has at their disposal, the better. Hopefully that will mean quicker fixes for these bugs that bug us!
Note: I contacted support initially a couple weeks ago. After not hearing anything, I called the 800 number which seemed to finally get the ball rolling. I'm really hoping Sony support will stick with me and help get these issues resolved. Wish I didn't have to deal with these problems in the first place, but the next best thing is to get them fixed quickly.