I always use project templates with 16 MIDI tracks preloaded, but I needed to add some to this project I'm working on. Every time I try to add one, Sonar freezes up. This isn't a normal freeze where if you click somewhere, the screen turns white and tells you that the program isn't responding. It's a complete freeze and clicking on the screen doesn't do anything. I have to force Sonar to close. I have no idea what could be causing this very strange and annoying behavior. Any ideas?  

Now every time I load that project it's frozen from the start!! Seriously, what the heck is going on? I can't even continue work on this project now. 

I was able to boot the project in Safe Mode. I chose "Yes to All" when it asked which plugins I'd like to load and everything is working fine. So, I know that it wasn't any plugin that was causing the issue. I'm afraid to try loading another track now, though. This is very frustrating...

It just froze again after simply recording some CC automation to a track. I'm thinking I might try rolling back Sonar versions since this never happened in the previous releases. 

Try opening the template in Lexington and re-save by overwriting the old one. If that doesn't work, try re-creating the template from scratch in Lexington. People have noted occasional problems with older templates.