dbmm
One thing that seems consistent is that Sonar or something in Sonar is hanging on to the drivers, because they are unavailable after the crash until I unplug the interface and force the process that's hanging on to the drivers to give up.

That is what I've seen here before and I'm sure it got answered but I can't find it...

Next time it hangs - try firing up Task Manager and seeing if you have something called BitBridge running.  If so, it means that one or more 32-bit plugins are running in Sonar, and this is a potential thing that can cause issues.
 
What I mean is that sometimes some 32-bit plugins just wig out when being 'bridged' to be able to be loaded and used in a 64-bit Sonar project.  A frequently seen symptom of that is to see BitBridge running when Sonar is hanging.
 
I WOULD like to see you run a test, where you launch Sonar, and then hold the Shift key when you open the project that seems to frequently hang Sonar.  This will tell Sonar to open this project in its 'Safe Mode', and it gives you the opportunity to pick and choose which plugins get loaded for this iteration of loading the project.  It will ask you for each plugin, if you want to allow Sonar to load it or not.  I would like you to NOT let Sonar load ANY plugins, and then I would like you to exit Sonar (no saving, just a regular exit), and then post back on whether or not Sonar hangs or crashes.
 
If Sonar does not crash or hang after the above, it would point to there being some kind of issue with one or more of the plugins associated with that project, and it then gives us something we can work through until we identify specifically which one(s) are causing the problems.
 
If Sonar STILL hangs/crashes, that is also revealing, as it means we need to look to some other cause for the problems.
 
By the way, if your latency is as high as it is - and you are recording, rather than mixing, I think you will want to revisit the settings for our ASIO Buffer Size (assuming you are running with ASIO drivers).
 
So please run the above test and post back, and when I get back from running my 84-year old mom to the doc, I will jump back in to tr to help.  Others will likely be assisting as well.  :)
 
Bob Bone
 

dbmm
Updated graphics driver, disabled low latency mode and was able to save without a crash. But when I went to X out of the program after the save.....it crashed.

Also check out this tip. It made a huge difference with my system, but results depend on multiple factors. 
 
Crashing while exiting usually involves a driver that doesn't release. Try closing the project from the file menu, then closing SONAR from the file menu.

In case it was not done after upgrading make sure to follow these instructions http://www.cakewalk.com/S...ommended-for-Upgraders

It can also be MIDI interface driver issues, not just audio, that prevent closing.

dbmm
That's whats so frustrating. Seems like I spend half my time diagnosing problems instead of creating music. Sometimes the crash occurs during save, sometimes I can save and when I exit it crashes. One thing that seems consistent is that Sonar or something in Sonar is hanging on to the drivers, because they are unavailable after the crash until I unplug the interface and force the process that's hanging on to the drivers to give up.

First of all...I hear you. Years of reviewing audio software has given me the "pleasure" of experiencing all kinds of anomalous behaviors involving various pieces of hardware and software from multiple manufacturers. One of the many reasons I've stuck with SONAR is because in my experience once you get it working, it stays working. Windows is not the best environment in the world for high-performance applications...great for spreadsheets, though 
 
Did you check for updated drivers from Roland? They made a big difference in my system. Also please check out the link to the tip in my previous post. No guarantees, but I used to have to set the latency high to avoid the problem you mention. Disabling that one driver let me reduce latency dramatically and still avoid crashes.

konradh
Since you say you have repeated crashes, I wanted to point out that after that white screen crash, I have to reboot the whole PC, not just Sonar, to get things working.
 
Also, someone remind me: can't you shift-click the Sonar icon to start it in a mode where it asks you about every plug-in/soft-synth?  Usually, you can start it without one or more plug-ins to isolate which one is the problem.
 
Extremely time-consuming if you have a lot of plug-ins, I know, but it is one way to find the one that is messing things up for you.  It looks like you don't have too many soft synths, so that helps.  I, unfortunately, have gone nuts on soft synths.

You can speed the process up though by instead of working through the plugins one at a time, enable half of them to anrrow the search down to 50% of your plugins.


Rinse & repeat as necessary

Just had another crash during save. Haven't had enough time to go through the plugins one by one yet. One thing puzzles me though. Once I've had a crash, if I reinstall the latest Sonar patch (E) it heals my system for awhile and I can save again. The problem is over time, it varies, the crashes come back. Install patch, it works again. Rinse and repeat.

What is the firmware of the Quad capture?
 
Be sure you are running the latest firmware (which is 1.04) with the latest driver (1.5.2)
 
Firmware and how to verify current version: http://www.roland.com/support/article/?q=downloads&p=UA-55&id=63053173
 
Driver (Windows 7/8/8.1): http://www.roland.com/support/article/?q=downloads&p=UA-55&id=62264894
 
I experienced the same exact behavior with Sonar x2 a while ago and I was using the v-studio 700 from Roland. I can't recall exactly what I done but I will let you know.  The firmware/driver incompatibility is something I remember caused problems.

Downloading updating. Will be out of town for a few days, will have to resume when I get back.