This is just a rant to make myself feel better. Maybe you can relate.
 
I'm a computer professional by day, helping customers at big companies get their data analytics working. On my commute, lunch and breaks I think about whatever song I'm working on for my next album. I'll play the song in my head and concoct exciting improvements to it. "Ooh, if I quote the bridge melody from this other song in the piano in that section, that will seque nicely into the key change..." that kind of thing. It's very satisfying. Then I get home and life happens, and maybe after the dishes and laundry and watering the garden and taking the lawnmower in to get repaired, I'll finally have maybe 45 minutes to work on music stuff. So I sit down in my man cave studio, rub my hands together, and dig in. And lo and behold, the entire time is taken up with figuring out why suddenly the instrument plug-ins aren't working, or why when I try to drag a clip over there the envelope gets screwed up, or why my record latency is suddenly slow, or, this or that or whatever, and hey, this feels exactly like I'm at work still, and BOOM, Sonar crashes, I have to reboot, and that's it for my music for the day. I go to bed and the cycle starts over.
 
Today is like that. I was going to adjust gain levels on the second section of this song, and decide if that flute figure works or I should cut it, but instead I'm looking at my plug-in manager, running a virus scan, and cracking open the manual for my midi controller. In a few minutes I need to wash the car and then start in on weeding in the yard. And I expect an email from my record label at some point this weekend asking why this album is taking so long.

Case in point: Decided the bass for this second section isn't beefy enough, but my rack mount synth doesn't have the right sound, so I decided to open one of the soft synths that come with Sonar. I haven't played with these a lot, but I should be more familiar with them. With fear that I'm going to go down another computing rat hole, I click on Rapture, only because it's one I've heard of a lot, so it must be important. And...Sonar crashes.

I feel your pain! I hate spending time I didn't plan on doing stuff that isn't at all related to the stuff I really want to do just to get to the point where I can start doing the stuff I really wanted to do in the first place. I would argue, however, that it's an issue that's not Sonar even Cakewalk, it's the state of computing itself.
 
As a software developer I've spent a significant percentage of my career beating my head against platform issues that shouldn't be there - broken SDK's, OS services, database engines that choke on simple operations, and on and on and on. It's maddening. The services a developer leverages to make software are supposed to abstract away the variability of the platform but they also introduce complexity and the potential for adopting someone else's mistakes or perhaps we don't fully understand their design intent, so we have to become semi-experts in just about everything our code touches just to keep it from biting our **** off.
 
A piece of software is such a delicate and fragile little beast, totally dependent upon a vast layer of underlying code that must be absolutely perfect every time for it to flourish. And all that assumes that you've written correct code yourself. It's a miracle that any software operates at all, ever.
 
I'll be the first in what will likely be a long line of posters to say, once you get your system stable, leave it alone! But as a computer professional I guess you already know that, right? :)

Okay, now that I've got my rant done, I will say that I've not had the instability in Sonar that you have been experiencing, so I'd venture to guess that something is really screwed up with your installation. :) You might consider reaching out to support to find out what you can do to determine the cause of the issues you are having.

Rarely do these things happen to me. I guess I'm lucky. I built my windows 7 machine solely for music. No email client, Microsoft office, Chrome, etc. I'm still on X3 and the machine is right there ready to go. I have the settings so it can not update anything in the background. Sometimes I turn it on just to do updates. It is possible to have it solid. Don't give up hope.

While my studio PC started off only for audio and video, i gradually added MS Office and all sorts of non audio programs and it too is as solid as a rock. I have no special settings, nothing, and its on a gigabit network as well. Only time I take it off line is if I'm actually recording and then only if I have to set my latency below 128.

SONAR is extremely reliable in my setup...but it's on a computer that's dedicated to music. I treat it like an appliance, or an MCI 24-track for that matter. I never expected to watch movies on an MCI 
 
I've certainly used programs that act the way you describe, and X1 wasn't exactly robust. But if someone has consistent, deal-breaker issues when running SONAR, that's not the norm - or this forum would be filled with pitchforks and torches. The solution is out there somewhere...and the last straw is that it's usually some simple thing that if only you had known about it sooner...

I had a very small number of crashes in Sonar X3. When the e patch the few I had went away pretty much. I can't recall a crash with Sonar Platinum. I'm sure I have had one but I don't recall it. To me Sonar is very stable on my system. 
 
I understand the frustration a crash will cause. I remember when in X2 with the click on the buss in the CV with Concrete Limiter on and get an instant crash was very upsetting. That crash lost a lot of work I had done. I didn't open Sonar for a week after it.
 
 
That bug is long gone. I can do anything I want and feel complete confidence nothing will go wrong. Stick with it and send those crash reports to CW. In the meantime upgrade to Platinum and things will work out.
 
One last point; because it is very complicated software there will aways be bugs in Sonar. We can hope that none of them impact us as we go about our working with the program.
 
If you read the posts here and the eZine of the fixes that CW has done as well as the ones to come you can bet Sonar will be better and even more solid as time goes on.  
 
 

Anderton
SONAR is extremely reliable in my setup...but it's on a computer that's dedicated to music. I treat it like an appliance, or an MCI 24-track for that matter. I never expected to watch movies on an MCI 
 
I've certainly used programs that act the way you describe, and X1 wasn't exactly robust. But if someone has consistent, deal-breaker issues when running SONAR, that's not the norm - or this forum would be filled with pitchforks and torches. The solution is out there somewhere...and the last straw is that it's usually some simple thing that if only you had known about it sooner...

+1
The fact the OP is doing virus checks leads me to believe this is a multipurpose DAW. My DAW is only online for CCC and other updates or downloads from known sites. My antivirus is up to date and runs in the background and I control installation of Windows Updates, drivers etc. Viruses (touch wood) are never a consideration.
Sonar is extremely reliable and stable - like the OP my time in the studio is precious, and it starts with a DAW that is solid and dedicated (though a bit long in the tooth at this point.)
Edit - I realize this post assumes a lot. If this were my daw, after removing and limiting other apps and avoiding unnecessary websites (maybe buy a cheap tablet just for browsing) I would spend a day or two checking my dpc latency and updating driver files, removing unnecessary windows services, etc.

jkoseattle
I'll finally have maybe 45 minutes to work on music stuff. So I sit down in my man cave studio, rub my hands together, and dig in. And lo and behold, the entire time is taken up with figuring out why suddenly the instrument plug-ins aren't working, or why when I try to drag a clip over there the envelope gets screwed up, or why my record latency is suddenly slow, or, this or that or whatever, and hey, this feels exactly like I'm at work still, and BOOM, Sonar crashes, I have to reboot, and that's it for my music for the day. I go to bed and the cycle starts over.

I do feel your pain. A lot of my creative days have been like that. Here are my suggestions for you, tips I learned the hard way.
 
1) Update to Platinum. Yes, I know we shouldn't have to pay extra to get bug fixes, but it is currently a fact of life. I had lots of crashes on 8.5, quite a few on X3, but only one in several months of using Platinum. (Yes, there are other bugs you get in exchange, but at least there is the prospect of them getting fixed; the bugs you have in X3 are going to be with you forever.)
 
2) Record latency is almost always down to 1 of 2 things: (a) your ASIO driver settings, or (b) a plugin you added. You can check the first in seconds and the second you can try and keep an eye on as you edit your project. The worst culprits for latency are convolution reverb/simulators and linear phase EQs, both of which tend to need to buffer up a lot of audio before they can start acting upon it. Get to know your plugins and watch for latency changes.
 
3) Don't run virus scans during music operations. If something is going wrong in your DAW then 99 times out of 100 it's a problem with plugins or settings. Viruses have better things to do than interfere with your music software.
 
4) Try to stick to 64 bit plugins. Bitbridge is a decent piece of kit but VSTs were designed to be run in-process without a middle-man trying to pass data between them and the DAW. With X3 probably half my crashes were related to various 32-bit plugins, and even now most of the problems I get with any plugins (especially those that don't initially make any noise at all until I change a preset) is because they're 32 bit and hosted in Bitbridge. Try to find replacements if necessary.
 
5) Try to do maintenance tasks at other times, not when you're trying to be creative. By that I mean organising your plugins, creating templates, etc. Then hopefully you can get straight down to business when you need to.
 
6) Clean up your computer. I don't subscribe to the "only use the PC for audio" belief - a desktop computer set up properly is capable of performing pretty much any task you throw at it. But be aware of competition for its resources. You may need to close other apps while working with Sonar, and you may need to ensure fewer background processes are running. Some people see a benefit by switching off wireless cards or other network drivers (because they can compete with Sonar for rapid CPU use). Similarly, programs like Flux compete for the graphics card, Crashplan competes for disk access, and so on.