Also verify the MD5 hash of the file you downloaded matches the one posted on the download page. A system restore point prior to the patch will restore the application to X3d, but the issue in the OP sounds a lot like a corrupt download or improper installation.

I think he posted it Bob 
 
Treefight is this happening on just one project or all, including a brand new project

Wow!  I usually don't miss something THAT big.
 
I'll get right on it.
 
Bob Bone
 

@Treefight, 
 
I am a little confused.  I went to the web site for your audio interface company, and their product versions don't quite seem to match your posted 'Lynx Aurora 16 PCIe'.  Here is the company's web site link:
 
http://www.lynxstudio.com/index.asp
 
I am asking about this because I wanted to see what their latest driver version is, and also I wanted to see if there is any firmware updates available.
 
Soooo, please find the product that exactly matches your interface, as I didn't find a ''Lynx Aurora 16 PCIe', and locate the most current driver release for your interface, and see if it matches what is on your computer already.  While you are there, look to see if there are also any firmware updates (have to be careful with these, but if one is out there, it may include a description of what changes are in it).
 
Thanks, I see you have a Sonar Sample Rate of 44.1 k, but you didn't list one for the interface.  It should exactly match the sample rate setting in Sonar, but I want to make sure that yours do match.
 
And, for the projects that are failing, are there any third-party 32-bit plugins loaded into any of them?  If so, please list which 32-bit plugins are loaded.
 
Bob Bone
 
 
 

So, Treefight, what's going on?  Are you still engaged in this thread?
 
The ball is in your court here, 
 
Bob Bone
 

Bob,
 
the Lynx pcie 16 is the pcie card - but it should have drivers.  It delivers AES or ADAT (with an ADAT daughter card) digital info to the computer.  The converters are separate.
 
@

OK - if this is the correct device, there is a drivers update from Feb of this year, as well as a firmware update from Feb of this year.
 
The release notes for the firmware update mention 44.1 k support.
 
Here is the link to the page with both updates (drivers and firmware)  - please make sure they are for YOUR exact audio interface.
 
http://www.lynxstudio.com/support_downloads_results.asp?prod=16&type=0
 
Bob Bone
 
 

@AT thanks - although I was not sure about the precise device, I did provide the link to the vendor's web site, and the OP had not provided the driver/firmware information that I had asked for earlier, so that was why I had urged him to remain engaged in the thread.
 
And, though I had asked for both, the OP had also not indicated what the sample rate for the audio interface was - he did supply the sample rate for Sonar, but one way to crash Sonar (and/or have other weird things happen) is to have a mismatch between the sample rates of the audio interface and Sonar.
 
Bob Bone
 
 

You are seriously over-clocking your cpu, and I would consider running X3 at normal speed to see if it becomes more stable.  I have encountered problems trying to run big complex software with over-clocking engaged.  X3e is a stable release. so the problem is likely with your system...

Well, there are some unknowns, and until he provides some responses with info that has been requested of him, there's not anything anyone can do for him.
 
Certainly this is system-specific, but could be from several different things.
 
Bob Bone