Impact of Compatability Mode (Win7) on Sonar in Win10?

I know that's a weird posting title and this may be a sort-of long post, but I hope you read it closely as I've spent most of this year on this problem of compatibility and you may face something like this, too.
 
I use the NI Kore 2 software a lot in my work, but when the year started, I was having issues with it. I had some year-end purchases and lots of updates, so I figured on finding something to revert or fix there. I use Kore so frequently, at least once or twice a month, it would have to have been something rather new or I would have seen it earlier.
 
However, I had exactly the same issue on a laptop and my living room media computer. They are all different machines and had lots of different hardware running, but they all had Sonar and Kore 2 and the latest version of Windows 10 Pro. I built the desktop (Core i7) and living room media center (Core i5) a few years ago (5 or 6). The laptop is Core i5 and rather new. All have been stable. 
 
You can read about these things in this thread on the Kore forum at NI:
 
http://www.native-instruments.com/forum/threads/kore-deep-freq-and-windows-10-crashes.313535/
 
I did lots of image restores and software re-installs in an attempt to isolate the problem; it has been a very painful year so far (insert crying smiley face icon here).
 
I think I finally solved it by setting Kore 2 standalone in Windows 7 compatibility mode. Since that works with the NIHardwareService rather intimately, I set it to be in Windows 7 compatibility mode, too. For about an hour I thrashed through that and think it solved the problem on my desktop and laptop. 
 
However, when you put the Kore VST in a DAW, it will run in the DAW compatibility mode because you can't change compatibility at the DLL level, only EXE.
 
So when I tested Kore in Sonar (and Live) it still failed until I change the compatability mode of Sonar and Live to use Windows 7 modes.
 
Now I have Sonar, Live, Kore 2 and NIHardwareService all changed to run in Windows 7 compatibility mode. It is possible that Windows 8 compatability would have worked, too, but I didn't try that.
 
I've run these DAWs in several ways with older projects and nothing seems broken at the moment, only time will tell. I rarely use Maschine or Komplete Kontrol, but as they use the NIHardwareService, I may need to change these and the other NI service for Komplete Kontrol... sigh.
 
I don't know exactly what these compatability modes mean. I think they pass flags to various APIs to alter the handling of some calls and internal branches. 
 
If this is truly the fix, and only time will tell, it may mean that we will all have to be careful about using older software as Windows 10 evolves.
 
For the record I have these versions (all 64-bit):
Windows 10 pro 1607 build 14393.693 (updated this week)
Sonar Platinum 2016.12 (updated a few weeks ago)
Live Suite 9.7.1 (from November 2016)
Kore 2 2.1.4.8329 (the last official release from Dec 2011)
NIHardwareService 2.0.2.150 (I think this came with the Maschine 2.5.6.2 update recently)
 
All the Sonar stuff is up-to-date according to CCC, NI stuff is all updated according to Native Access, etc. I try to keep everything tidy.
 
I hope this does not impact anything else. I'm likely to forget about this setting in a few months, so if something does surface later it could be a lot of trouble.
 
Windows used to have hardware profiles that would let you boot with different components, but there is nothing I know that would allow different compatibility modes to switch on demand.
 
I hope this helps someone else, I spent an enormous amount of time and lots of tears over this.
 
If anyone has ideas about what might happen using this mode with other stuff, or know more about how this works, I am eager to learn.
 

Thank you. I have independently discovered that discussion you posted in my searches as well as some code examples about the shim feature.
 
I'm hoping that someone at NI will take a look at this problem. Kore 2 uses the NIHardwareService, but that service is being enhanced for the newer Maschine and Komplete Kontrol line. I doubt if they regression test the service using older discontinued software. It is clear that there is no Kore support, but this is a bit different.
 
So far after about a day's work I have not seen any issues, and older Sonar X3 projects still load and run fine.
 
I wish it were as simple as running Resource Monitor in the background.
 
Kore 2 is very important to me. Reaktor and Kore are the most used music software in my room.
 
I could probably replicate the Kore programs I use with Guitar Rig, Reaktor, some Melda effects and Blue Cat's chainer, but it would take a long time and I'd rather be making sounds than software.
 

I used ProcMon to find where the compatibility stuff is located. The cache is in the registry at:
 
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\
 
Interesting to see what is saved there for the various files. 

For the sake of thoroughness, and as l have invested a significant amount of time in this, I want to add two more points to this thread in case it helps someone else:
 

1. when a program runs in a compatability mode, an environment variable is set. For example with Windows 7 compatability, I see: 

   __COMPAT_LAYER=Win7RTM DetectorsWin7

2. Uninstalling and re-installing under a compatability mode will not change the compatability mode of the installed program. I did not see any difference in behavior when I performed that test.