Doktor Avalanche
I wonder what happened with the original poster?

The original poster has things to do... Hehehehe! Sorry for going quiet but was in the middle of an unexpected move while all this was going on.
 
Anyway, I will take a look tonight as the suggestions above and see if anything helps. Sonar X2 on the other hand is stable and no issues with the same project. This definitely looks to be a Platinum issue?
 
Take it easy on the HiJacker, I have no issue with his input on my post.

Platinum used to work fine until I upgraded from win 7 to win 10. I think I may need to upgrade my interface.

I went a year and a half and recorded an entire 12 song CD using X3 and never had a problem.  I switched to Platinum on New Year's day 2015 and my system crashes on me at least 3 or 4 times a session.  the fix is simple, go back to X3.  I think I'll stay there until they figure out how to stablize Platinum

Platinum is stable on the vast majority of systems.
 
If I were you, I'd start a new thread of your own, listing your entire system spec and the sort of things you do to provoke a crash

Is it possible your audio interface could have gotten plugged into a USB 3 port, rather than USB 2?  Sometimes, audio interfaces freak out and flake out Sonar and even Windows when they aren't able to handle USB 3 for some reason.
 
Also, have you tried opening your project in Sonar's 'Safe Mode' by holding down the Shift key while opening the project that is failing?  While safe mode is launching, you will be asked whether or not you want to load each/all plugins, and I suggest for the first go round that you skip the loading of ALL plugins, to try to get just the Sonar engine itself running with the project's tracks - no effects and no soft synths.  THEN, just try a few things, but don't save it while in Safe Mode, just try some stuff out and see if it still fails.  If it stays up, then perhaps a plugin is freaking things out (many times a left over 32-bit plugin might not like running in a 64-bit Sonar).  You might consider backing up your project file first, before you try this, just in case you accidentally save it.  :)
 
And, do you by chance have any hard drives that are 'green'?  (variable spin rates) These can often really have a bad hair day in Sonar, for some reason.
 
And, are you sure your Sample Rate in Sonar matches the Sample Rate set for the audio interface?  This too can sometimes wig out Sonar.
 
Also, you might try temporarily suspending your antivirus software, or adding any Sonar paths to its exclusion list, as this too can sometimes cause issues.
 
Lastly, did you use Cakewalk Command Center to do the Platinum installation?  If not, perhaps you might want to let it handle it - first making sure you have downloaded the latest version of Command Center.  
 
Bob Bone
 

I would recommend running LatencyMon, even if you don't know much about what it is reporting on, at least it will give you an idea of what your system is having to deal with as well as Sonar. I, like the others have had Platinum running fine for some time and the only crashes I have had so far is on a project with 55 audio tracks, a small number of Aux tracks, 9 busses and 42 instances of plugins (not to mention a number of different instances of pro channel modules). Notably the thing that tends to send the project over the edge is adding yet another wafer thin Waves VST 3 plug-in (Mr. Creosote style), so I suspect they may be more processor/memory hungry than others. As the load got larger I have had to increase the ASIO round trip, which is not an issue when in playback and it is still smaller than when I run PT on the same machine with a lot less tracks.
I am about to add another 8Gb of Ram which may give me a bit more headroom, but considering the loads I have put on the system, Platinum has done sterling work.
 
P.S. forgot to add, the project also had three instances of drum replacer, two instances of Vocal sync and two instances of Autotune

1. latency mon.
2. open sonar by holding shift key down it does something to the registry.
3. try the delete aud.ini file.
4. rollback to earlier iteration.
 
The question is why do we have to do all these things!  I've been back and forth with customer service, we have no idea why sonar out of the blue started hanging while opening.  It happens randomly.

eph221
1. latency mon.
2. open sonar by holding shift key down it does something to the registry.
3. try the delete aud.ini file.
4. rollback to earlier iteration.
 
The question is why do we have to do all these things!  I've been back and forth with customer service, we have no idea why sonar out of the blue started hanging while opening.  It happens randomly.

I guess the answer is, you don't have to do all these things if your system doesn't have any issues. If Sonar is running fine for others, the question is really "If the software is the same, why doesn't it work on my set up". In order to determine that, you need to logically troubleshoot and eliminate possible causes. Hence the suggestions above.
As others have pointed out , the cause(s) could be singular or multiple. It could be hardware related, operating system related, driver related, software related and/or configuration related. There are just too many variables for someone to accurately diagnose this based on some information in a forum post. Hence why the helpful people here will ask questions and suggest answers based purely on what information you can provide.

So what I am using in Platinum, Liquid Saffire 56, Windows 7 i7 chip, 64 bit, 16G Ram and according to the specs I am on the latest versions of Saffire and Platinum.  I wanted to go to W10 but I couldn't get it to recognize the Saffire interface.
 
I get that there might be some element of user error here, but I do know that when I stop using Platinum and go back to X3 I have zero issues.  Currently I am using X3 to complete everything in the recordings and then using Platinum only for one of the new Pro Channel reverbs that I like.  As frustrating as this might be, I am grateful that I have a very reliable alternative working for me.

Forgive the addition...it might be helpful to point out I am using a UAD quad card with a significant amount of plugins being used within the recordings and I am connecting to Saffire via firewire.  Again, working in X3, crashing frequently in Platinum.  I think that's everything.   :)
 
I also wanted to say I appreciate this thread, so thank you to all the contributors.