I left for the holidays for 8 days and now the last project I was working on crashes Sonar.  All other projects seem to be fine.  I installed the X2a patch 64 bit and that did not work. Here are some specs on my system:
 
X2 Producer
Windows 7
Intel Core i7 CPU 2.80 GHz
12 GB ram
64 bit
 
I know this is older stuff, but outside of the occasional glitch in Sonar, everything has been working great.  I did have a lot of midi instances in this particular project, but it is the same template I have been using for quite some time with no issues. The libraries include Kontakt 5 (many instances), Trillian, EZ Drummer 2, True Pianos.
 
Are there any other patches out there I am missing? Any other suggestions? 
 
 

I would suggest Shift+Opening the project so you can load without any plugins just to confirm whether that's where the issue lies.  If so, you can repeat and add a plugin or two at a time to narrow down which is causing the problem.

stevec
I would suggest Shift+Opening the project so you can load without any plugins just to confirm whether that's where the issue lies.  If so, you can repeat and add a plugin or two at a time to narrow down which is causing the problem.

Thanks I'll give that a try.  Do you just hold down the shift button and then open the project?

Yup, just hold down the shift key while selecting the file to open.   That should give you safe mode dialog where you can choose to open with all plugins, bypass all plugins, or one plug-in at a time to help narrow things down.