WTF happened? Everything was running smooth as silk, then all of a sudden, during periodic auto-saves I get an instant crash, no hope of saving anything. I started a new project as a test, then hit save, instant crash. I have plenty of gigs left on my data drive, I haven't installed anything new in the last few months, and then all of a sudden this starts. What the heck is going on? Help!

That is rather odd. What are your I/O buffers set to (Advanced Mode: Preferences->Audio->Synch and Caching)?
 
If something just "suddenly happens," it is often a change to system configuration. Did you install or modify your machine any before this began happening?

I've changed nothing. The only change that happened is Windows did some auto-updates.
 

Run chkdsk and check your event viewer I suggest.

nullobject
I've changed nothing. The only change that happened is Windows did some auto-updates.

If it's been ages since your drivers have been updated now is probably the time to consider updating them, but check event viewer first + chkdsk I suggest.
http://forum.cakewalk.com/m/tm.aspx?m=2928792
 

After looking in event viewer I show 3 events after 3 attempted saves-Session "Microsoft Security Client OOBE" stopped due to the following error: 0xC000000D

The weird part is saving a project that is blank also causes the crash.

It "appears" that MS Security Client is attempting to virus scan your project during the save. If you disable that when running X3c, does it resolve this?

I don't know where that would be?
 

Are you using any other virus scanner other than Microsoft security essentials? If so they could be conflicting.


If not please uninstall MS Security essentials, reboot and then reinstall:
http://windows.microsoft.com/en-GB/windows/security-essentials-download
 
Any further errors in the event viewer please give us the full error, there are copy faculties within the event viewer itself.
And we have no idea about your environment, would it be possible to update your footer to look similar to mine?
 
Thanks...