Why doesn't Silverlight 5 work well on Mac OS X 10.8.2?

I have clients showing me basic Mac OS X dumps that show that calls made on Mac OS X cause a signal interrupt (SIGABRT) by opening the default Silverlight preferences on the Mac. Also, our Silverlight 5 application won't run on this machine.

By Silverlight 5, I mean 5.1.10411.0.

Customers who seem to be having the most problems are using Mac OS X 10.8.2 (latest mountain lion)

I have a Mac that works fine with Silverlight 5, but it's Mac OS X 10.6.8 (Snow Leopard). Our app also works as expected on this Mac.

There is a lot of evidence on the internet that many people have the same problem. There are many supposedly "miraculous" solutions out there, but it doesn't seem like end users will have to jump through hoops to get this to work. People who have Netflix problems on Mac computers and problems when a program called MacKeeper messes up Silverlight installation. I just want to know what is causing such problems? Isn't Microsoft consistently testing Silverlight well when the Mac comes out with a new version of Mac OS X, or would it be more likely that Apple is deliberately trying to subvert Microsoft Silverlight (and other programs, apparently) on purpose for some reason? There seems to be a lot of random crashes happening on Mac OS X 10.8.2, with Microsoft Office and other non-Microsoft applications.Can anyone understand the reasons for this? Does Silverlight support Mac OS X 10.8.2 on your computer?

Who is to blame for this? Apple or Microsoft? Both? No?

Microsoft has said it plans to support Silverlight until 2021. Is there a subtext that is really only supported on Windows? The whole point of making an application in Silverlight in the first place for many decision makers would be so that it can run on a Mac. Why Apple and Microsoft can't play well, at least in this particular case where interoperability is demonstrated and marketed as something you can rely on to just work. (Why can't we just get along? Stop. That was rhetorical.)

Did Microsoft test Silverlight on an earlier version of Mac OS X just to have Apple change something in the next version of Mac OS X?

Are my clients and other people on the Internet doing something inappropriate, like running third-party utilities that break the Silverlight installation process?

Will it end up being just a permissions issue?

Is Mac OS X 10.8.2 just a bug or generally unstable? Are there any other apps that just crashed into Mountain Lion? What needs to be done to avoid this - Apple dropped some of the API calls?

Theories, speculation, insider ideas and other types of input are all welcome!

Please just do not resort to passionate beating of legal entities as it is pointless. I just want to know how it can be ironed out and who is called to make it happen. I don't want to know who is "evil" - I just want to know who is not doing their job right.

Here is the thread that falls on Silverlight just trying to show its settings:

> Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib          0x9114da6a __pthread_kill + 10
1   libsystem_c.dylib               0x99467acf pthread_kill + 101
2   libsystem_c.dylib               0x9949e4f8 abort + 168
3   com.microsoft.net.coreclr       0x0a00b8d4 0xa000000 + 47316
4   com.microsoft.net.coreclr       0x0a00b958 0xa000000 + 47448
5   com.microsoft.net.coreclr       0x0a00b3e8 0xa000000 + 46056
6   com.microsoft.net.coreclr       0x0a103b27 GetCLRRuntimeHost + 193895
7   com.microsoft.net.coreclr       0x0a037553 PAL_InitializeCoreCLR + 58243
8   com.microsoft.net.coreclr       0x0a10130c GetCLRRuntimeHost + 183628
9   com.microsoft.net.coreclr       0x0a101445 GetCLRRuntimeHost + 183941
10  com.microsoft.net.coreclr       0x0a1069a6 GetCLRRuntimeHost + 205798
11  com.microsoft.net.coreclr       0x0a106b5b GetCLRRuntimeHost + 206235
12  com.microsoft.net.coreclr       0x0a1c94be GetCLRRuntimeHost + 1003262
13  com.microsoft.net.coreclr       0x0a1ca005 GetCLRRuntimeHost + 1006149
14  com.microsoft.net.coreclr       0x0a27a5ea GetCLRRuntimeHost + 1728554
15  com.microsoft.net.coreclr       0x0a339c94 GetCLRRuntimeHost + 2512596
16  com.microsoft.silverlight       0x000050ac start + 5624
17  libobjc.A.dylib                 0x9279e586 -[NSObject performSelector:] + 62
18  com.apple.CoreFoundation        0x90f1bb64 -[NSSet makeObjectsPerformSelector:] + 228
19  com.apple.AppKit                0x97263011 -[NSIBObjectData nibInstantiateWithOwner:topLevelObjects:] + 1180
20  com.apple.AppKit                0x97241572 loadNib + 373
21  com.apple.AppKit                0x9724094a +[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:] + 233
22  com.apple.AppKit                0x973919a4 +[NSBundle(NSNibLoading) loadNibFile:externalNameTable:withZone:] + 154
23  com.apple.AppKit                0x9724061f +[NSBundle(NSNibLoading) loadNibNamed:owner:] + 709
24  com.apple.AppKit                0x9723c498 NSApplicationMain + 447
25  com.microsoft.silverlight       0x00003baf start + 251
26  com.microsoft.silverlight       0x00003add start + 41