I have too suffered this in the past and ranted a few times on the forum about it.
 
Hasn't happened for a while now (touch wood)

LJB
The more you can educate your users, the less trouble you have.
 
Ludwig

Google! Or read the forums every day and educate yourself. Generally driver, firmware, plugs or not keeping your maintance up to date. Educating yourself is your responsibility nobody else's :)

Doktor Avalanche

LJB
The more you can educate your users, the less trouble you have.
 
Ludwig

Google! Or read the forums every day and educate yourself. Generally driver, firmware, plugs or not keeping your maintance up to date. Educating yourself is your responsibility nobody else's :)

 
Bit of a glib reply there Doc. I do what I can when I have the time, but I expect paid-for stuff to work, so that I can have the means of paying for it :O)

More to the point, it's fine to say users should get educated, and I of course agree, but if a service or product provider wants less traffic in the complaints dept and more available resources in the R&D and Sales dept, they need to make the essential info available to the users in an-easy-to-understand format. That's why, for instance, some ISPs are giving away free routers - so that one less unknown is removed from the equation. And that's why trouble-shooting checklists have been part of gear manuals for years. It saves time and money in the end.
 

Maybe glib but I mean every word :) If you are integrating software and hardware from various suppliers and you have issues it's nobody but you who is going to resolve it. Or hire somebody to do it for you. Or ring up the various support channels on offer, although they can only deal with specific ssues. Forums is on hand to help and there is a wealth of information at your fingertips you aren't exactly the first and you won't be the last :)

So here we all are in the same boat. This is the internet there is a ton of information here, and esp within these forums.

Hope you get your issue resolved.

LJB
Well, this problem has been around for several Sonar versions, under various error messages. I had Win 7 Ultimate and now Win 10, which is luckily more stable, except for that error.
It may well be worth Cakewalk's time to write some sort of a PC/OS debug tutorial then - even if it's not their bug. Where the heck do I even start looking - I make music!
The more you can educate your users, the less trouble you have.
 
Ludwig

Definitely something specific to your environment if it has been around for several versions. Its not the driver since I have the same interface and never have this issue. To troubleshoot you should see if there is something specific to your projects that causes it. Use a process of elimination - start with any project and keep removing tracks and plugins and saving versions until the hang stops happening. Then back track and find what you changed. 
Obviously we can't fix it if we cannot repro the problem or understand better what is causing it on your setup.
 
PS: Also to start out eliminate all other hardware - disable your MIDI interface, remove any control surfaces etc and see if the problem still occurs. There have been some MIDI drivers that hang on exit.

What I find perplexing is that my Roland Quad - as mentioned in my last post - routinely hung after Plt stopped working. Now with the same project - nothing else changed in terms of vst's etc - and using RME UFX drivers, this doesn't happen. Even if Plt crashes - rare - the drivers are released almost immediately. I'm don't have the time - or tech head - to 'nut this out'. I'm just grateful that this on-going issue is solved. 
 
The only thing I would speculate is that I now use the Quad for Windows-related sound activities - like listening to utube, or playing an mp3/wave etc - and only use the RME for Sonar or mastering - which is what they recommend.

You might be best to use something like Process Explorer or Process Monitor from Microsoft and start digging into the system to see what processes are locking on what. Is a process hanging on a registry entry, a permissions issue, a file locking problem.
 
I use Process Monitor quite heavily for troubleshooting application problems through my IT job. It will tell you everything a process is trying to do when opening, running, closing from opening files, accessing registry entries etc. It can be quite daunting to use at first, but once you figure out filtering options and start looking you might just stumble on what is causing the problem.
 
If I get time I'll have a look at my system later on and see if I can write a quick how-to that might point you in the right direction. Thought I would just mention it quickly to get you started.
 
EDIT: Found some resources to help with using Process Explorer:
http://www.howtogeek.com/...rnals-pro/lesson3/all/
http://www.howtogeek.com/...rnals-pro/lesson5/all/

Windows event viewer...

Fabio Rubato
What I find perplexing is that my Roland Quad - as mentioned in my last post - routinely hung after Plt stopped working. Now with the same project - nothing else changed in terms of vst's etc - and using RME UFX drivers, this doesn't happen. Even if Plt crashes - rare - the drivers are released almost immediately. I'm don't have the time - or tech head - to 'nut this out'. I'm just grateful that this on-going issue is solved. 
 

I think this is a Roland specific driver issue that you cannot sort out yourself anyway.
 
I'm seeing similar issues with Octa-Capture and VS-700, both Roland. Sometimes master out goes silent (and requires Sonar restart or changing ASIO buffer size to re-init audio drivers), sometimes it hangs when closing Sonar and sometimes Sonar exists normally at end of session but the DAW does not shut-down as the driver got stuck in the background keeping windows from shutting down ...
 
Good thing is that these drivers are no longer maintained (at least the VS EXPAND version of it that gives you all the I/O) and eventually I will migrate to RME (I hope you sense the irony)

I haven't had this issue since I ditched my old MidiSport 8x8 MIDI device several versions ago.  I figured out then that it was the culprit and would simply shut it off when it hung, wait a few seconds for good measure, then turn it on again.  The process would die when I shut it off, and then the OS would pick it back up when I started it again.  Fortunately I don't use external hardware synths any more, so I sold the MidiSport and don't have the problem now.
 
The only advice I can give is to do some testing (Noel's method looks pretty sound) and figure out whether it's a bridged plugin or a driver.  Personally, I'd suspect hardware first, plugin second, unless you do a lot of bridged plugins.