I figured it was time to get it over with, so I updated Platinum and I updated my OS to Windows 10 and it seems that the latest ordeal started with the Focusrite Drivers.
 
I followed the instructions from Focusrite saying that I needed to update to Scarlett MixControl  v1.9b10.  I did so--even though it is still a Beta--because the original driver would not let me adjust Asio Buffer size.
 
Now, I can open older projects, but I cannot get acceptable latency for vocals--I get a noticeable delay. I can lower the Asio buffer size (even though I still can't seem to get it low enough to get rid of the delay), but when I try to raise it back, Sonar crashes.
 
And on my most recent project, Melodyne causes Sonar to crash before it can even open.
 
I tried uninstalling the new MixControl, then re-installing older MixControl (it seems that the MixControl and Scarlett drivers are inextricably tied together), and the older version doesn't crash, Melodyne doesn't cause a crash on the recent project, but then I cannot change the Asio buffer size!
 
I also tried re-installing Melodyne, no help.
 
 Anybody point me in the right direction here?
 
 

1) Uninstall mix control
2) Reboot
3) Install mix control
4) Reboot
5) Go to mix control, reset the hardware and other settings to the defaults
6) Set up mix control again...
7) Save any settings you have to hardware (assume there's an option there, there is with saffires).
 
Other things you might try:
 
A) Update your BIOS
B) Update your chipset drivers on Intel driver update website.
C) Update your display driver
D) Run windows update.
E) If you are running or have run ASIO4ALL in the past - remove and uninstall it now!!
F) Temporarily disable your virus scanner and disable your network adapters.
G) Delete AUD.INI in Sonar (google for details)
 
Cheers...

I followed your instructions, including updating BIOS, chipset, etc.  I had actually deleted ASIO4ALL after I updated to Windows 10 and I am using ASIO.
 
The problem persists, but only in this one project.  I have done 3 versions of the same project, re-saving  periodically in case of problems.  The previous two versions of this project are fine.  It seems to be just this last version that has a problem.
 
I would hate to roll back a version--I have accomplished a lot since.  So, what might I inadvertently  done that would cause driver latency and melodyne crash?  My audio settings should be the same for all versions.  I have checked what I know, and the settings match up.

A single project...
 
OK
 
Try PDC override.
Try ruling out conflicting plugins.
https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=Dialogs2.094.html
 
You could try bundling and then unbundling the project to see if it clears anything..
Worst case scenario. Create a brand new project and copy and paste your data from old into new...
Ta.

Dupe.

Thank you, I'm not sure which plug in did it, but after eliminating, I am now able to open without crashing.
 
However, there is still something amiss in this project--it almost seems like something is either looping, or using up too much processing power, even though processor only shows 32% and most of my tracks are frozen.  I can't see anything obvious where I have looped...channel strips are feeding buses, effects sends are feeding effects in a bus and buses are feeding the master.
 
The symptoms are: slow loading, sometimes clicking (even though I have adjusted the ASIO settings), which does disappear after a few seconds; also, sometimes upon boot up, I will get a click and a surge and my master meter will pin in the red and I have to re-start. There also seems to be somewhat of an overall reduction in level, and a little extra latency that is not present in other projects.
 
I came across something like this before, and I would like to figure what I might have done wrong so I don't keep doing it.  If you have any ideas, I'd appreciate it.

Suggest...
 
Make sure you've completed post #2.
In windows go into advance power management and make sure your min/max CPU settings are on 100%.
Defrag.
Consider disabling unnecessary windows startup app and services (Google for details).
Run latencymon/process explorer/process monitor utils.
 
Cheers...

Why bother going to Win 10?   What are you really gaining?   Is it really worth the trouble you are having with your HW and you haven;t even gotten to any plugin or software issues yet....   Personally,  I did the Win 10 upgrade and immediately had issues with Firewire and some other things so I just reverted back and I am as happy as can be as my system (computer AND software work perfectly on Win 7 as they have for quite sometime).   I stayed with Win 7 as it will e supported through 2020.   I can't imagine Sonar Platinum  stopping Win 7 anytime soon and even if they did... what more can they possible give us that would make our recordings sound any better (or worst)?   It already can do SO MUCH!  So again.. why bother?   Just wait until you HAVE to move (i.e. machine obsolesence etc) and by then there will be a whole new set of tools and toys!

It is actually not Windows 10 causing this problem. By post #3, I had discovered that this is only happening in this particular saved version of this project only. Earlier versions are fine. Something happened (or I inadvertently did something in this latest incarnation) that is causing some kind of latency/cpu issue.  I don't know enough about anything to really understand what is going on. It's just that this happened to me once before (in Windows 8.1) and I am trying to figure it out so I don't keep doing it. 

Even if Windows 10 wasn't at fault with your Sonar project issue, its still an epic privacy, self-determination and computer ownership violation.
 
Microsoft would like to start treating YOUR computer like its theirs, control it, lock it down like its an Xbox or PS4 console. Windows 10 is another major step in that direction. Among others:
 
- UEFI may have some useful and needed improvements over the old BIOS, but this modernization has also been misused to introduce various measures that offer more control to OS and hardware manufacturers and less control to actual computer owners who paid good money for that plunder. 
 
- Same as Intel's in-hardware security features baked into all their recent CPU's amount to nothing but omnipotent back-doors.
 
 
I will be upgrading to Win10 only after about a year, when drivers have been optimized and privacy software packages blocking Microcruft's tentacles have matured.
 
Not like I even have anything for them worth seeing, but one's gotta have some principles, especially in the face of a slowly creeping process that isn't going to stop if everybody just takes it. 
 
Your LG "Smart" Television already asks for permission to listen in and record your skype conversations and also use YOUR bandwidth to send advertising for themselves and their 'partners' to your TV.  If you don't agree, no "Smart TV' functionality will be available at all.  If you don't send it back, they'll ask for your first born next time.