SONAR.EXE has stopped working HELLLP!!

Is it Sonar you start and not Sonar with a loaded file? Its likely that a plugin is causing Sonar to crash.

Did Sonar crash or did Windows crash... i.e., did you get the BSOD? What version of Windows? What version of Sonar?  What soundcard?

Look in the Windows Event Log and see what may have happened to cause the crash.

You should also run a CHKDSK on your system drive.

Basically uninstall, back up the registry just in case and delete the following 2 keys (assuming you have Producer).

HKEY_CURRENT_USER\Software\Cakewalk Music Software\SONAR Producer\8.5
HKEY_LOCAL_MACHINE\Software\Cakewalk Music Software\SONAR Producer\8.5

This will remove any custom settings so save those too.

You still haven't indicated what sound card you are using.  What error messages are you getting?  Did it complete the vst scan on first start up? Did it reprofile your sound card on start up?  It sounds like may have a problem with your sound card.  Have you checked all the connections?  Does your sound card put out sound when using a stand alone plug in? Have you installed any updates recently for plugins/ video card etc?.  

Does it only crash when you try to open an existing project or does it not even get to the point where you can select a project to open?  Are you using 32bit Sonar or 64bit?

Information is needed before anyone can offer any significant suggestions.  I have never run into a problem that required a reinstallation of Sonar.  Any problems I have had have usually resulted from updates, installation of new hardware that is conflicting with existing drivers/hardware, Windows updates, iTunes updates(especially Quicktime) video driver updates, vst updates, and even Internet explorer updates.

Think back to when the problem started and try and remember anything you changed/updated/added to your system just prior to the problem occurring and that might get you pointed in the direction where you can find a solution. 

Some random ideas:
1. Have you downloaded and installed the latest drivers for your audio interface?
2. Doesn't Sonar have a 'Safe Mode' startup option (where it doesn't load plugins etc on startup)? I'm not sure how to use it off the top of my head, but maybe it's worth a shot?
3. Try running Sonar as Administrator. I had some Sonar crashes on startup once because a plugin needed admin rights to do something on it's first run.
4. If you are trying to open the project that originally crashed, could one or more of the audio clips be corrupted? Using Windows Explorer, go to your projects audio folder and try listening to the WAV files using Windows Media Player. If they sound fine, great, but if Windows Media Player refuses to load or play them properly, then maybe that's your problem?
HTH

He confirmed it was Sonar, not Windows crashing.

I have lost multiple clients from this embarrassing event and am ready to do whatever it takes to continue recording... even if that means switching DAW's   :*[

As stated above Changing DAWS will not solve your problem. You need to post a clear list of what you are using so we can help you. I see you posted a year ago and never did answer the request for specs. This form is a valuable resource, use it wisely. It's one thing to be using the software as a hobby and get in a bind but if your using it to earn a living might be time to dig in and get a handle  on it. There are many things that can go wrong, list your system and lets have a go at it.

Well to add my 2 bits I'm having the same problem and nothing seems to work. I tend to think it's a vst plugin because when I load mopre than 2 plugins is when it happens and |I get crackling or buzzing times fragments of sounds when I use tho0se pluigins. No solution yet. I'mn using windows 7 because when I used windows 10 it was totally screwed up and the Delta 10/10 lt soundcard doesn't have drivers for Windows 10. No wonder cakewalk sold out.
 

Here is a link about how to start Sonar in "Safe" mode so you can choose, one by one, which plug-ins to load. I have done this once in the past when I had a project crash on startup and it was an older 32-bit plug-in compressor I liked to use. Finally had to bite the bullet and find a newer 64-bit compressor.  But regardless, maybe this will help troubleshoot.  http://www.digifreq.com/digifreq/tip.asp?ID=10
There are also older posts on this forum explaining safe mode.