This one is hard to figure out which component it belongs to. I see this when running a build with JAWS enabled. Hundreds and hundreds of these messages.

And Brett mentioned the same thing on his side. That it really hinders debugging.

I think that is: https://msdn.microsoft.com/en-us/library/microsoft.visualstudio.vsconstants.disp_e_badvartype.aspx?cs-save-lang=1&cs-lang=cpp#code-snippet-1 Not much to go on... Maybe a COM method variant arg doesn't like what is passed? Aklotz probably has more sensible ideas...

So one interesting "feature" of distributed COM is that internally it uses exceptions for error handling; it catches them at the public API layer and then returns them as the HRESULT error code. That's why you see all kinds of debugger spew but it never seems to actually crash. To our code and JAWS' code, 0x80020008 would be returned from a COM call. One thing that helps to debug this is to configure the debugger to break when it encounters such an exception. Then at least you can see a call stack. In WinDbg you can go to Debug -> Event Filters... then select "Unknown exception" from the list and select the "enabled" radio button. I'm not sure how to do this in Visual Studio, sorry.

Thanks Aaron, I found a similar option in Exception Settings in Visual Studio - Check Win32 Exceptions. Here's the stack: KernelBase.dll!749ea832() Unknown [Frames below may be incorrect and/or missing, no symbols loaded for KernelBase.dll] [External Code] > xul.dll!mozilla::mscom::Interceptor::GetInterceptorForIID(const _GUID & aIid, void * * aOutInterceptor) Line 324 C++ [External Code]

Can you tell me what the value of the aIid param was? I probably need to know which interface was involved in order to track this down.

Sorry, Aron, can't get the same stack again, but I do have this one: KernelBase.dll!_RaiseException@16() Unknown rpcrt4.dll!RpcpRaiseException() Unknown rpcrt4.dll!_RpcRaiseException@4() Unknown combase.dll!NdrExtpProxySendReceive(void * pThis, _MIDL_STUB_MESSAGE * pStubMsg) Line 1965 C++ rpcrt4.dll!NdrClientCall2() Unknown OneCoreCommonProxyStub.dll!_IServiceProvider_RemoteQueryService_Proxy@16() Unknown OneCoreCommonProxyStub.dll!_IServiceProvider_QueryService_Proxy@16() Unknown oleacc.dll!AccWrap_Base::QueryService() Unknown FsDomNodeFirefox.dll!5ae23a9f() Unknown [Frames below may be incorrect and/or missing, no symbols loaded for FsDomNodeFirefox.dll] FsDomNodeFirefox.dll!5ae24282() Unknown FsDomNodeFirefox.dll!5ae24019() Unknown FsDomNodeFirefox.dll!5ae2073e() Unknown FsDomNodeFirefox.dll!5ae27736() Unknown FsDomNodeFirefox.dll!5ae175ea() Unknown FsDomNodeFirefox.dll!5ae1775a() Unknown [External Code] FsDomSrv.dll!530c13a6() Unknown > xul.dll!js::LiveSavedFrameCache::~LiveSavedFrameCache() Line 1190 C++ [External Code]

Sorry, misspelled your name, Aaron

Is this still an issue with today's trunk?

I don't see this exception any more however I see this exception frequently now, sorry wasn't able to get the stack just yet: Exception thrown at 0x7634A882 (KernelBase.dll) in firefox.exe: 0x8001010D: An outgoing call cannot be made since the application is dispatching an input-synchronous call.

I don't see this exception any more, however I see this one pretty frequently now: Exception thrown at 0x7634A882 (KernelBase.dll) in firefox.exe: 0x8001010D: An outgoing call cannot be made since the application is dispatching an input-synchronous call. KernelBase.dll!7634a882() Unknown [Frames below may be incorrect and/or missing, no symbols loaded for KernelBase.dll] [External Code] FsDomNodeFirefox.dll!662acfe2() Unknown FsDomNodeFirefox.dll!662ad35c() Unknown FsDomNodeFirefox.dll!662b04dd() Unknown [External Code] FsDomNodeFirefox.dll!662a2660() Unknown FsDomNodeFirefox.dll!662a0596() Unknown FsDomNodeFirefox.dll!66297429() Unknown FsDomNodeFirefox.dll!6629b1d2() Unknown FsDomNodeFirefox.dll!66299a88() Unknown FsDomNodeFirefox.dll!66297d23() Unknown [External Code] FsDomSrv.dll!621c13a6() Unknown [External Code] FsDomSrv.dll!621bead5() Unknown [External Code] FsDomSrv.dll!621bf048() Unknown > FsDomSrv.dll!621bf05a() Unknown FsDomSrv.dll!62162f50() Unknown xul.dll!mozilla::net::AltSvcOverride::Release() Line 1105 C++ xul.dll!nsContentUtils::AddScriptRunner(already_AddRefed<nsIRunnable> aRunnable) Line 5335 C++ [External Code] xul.dll!nsGlobalWindow::UpdateCommands(const nsAString_internal & anAction, nsISelection * aSel, short aReason) Line 9913 C++ xul.dll!mozilla::dom::WindowBinding::updateCommands(JSContext * cx, JS::Handle<JSObject *> obj, nsGlobalWindow * self, const JSJitMethodCallArgs & args) Line 5281 C++ xul.dll!mozilla::dom::WindowBinding::genericMethod(JSContext * cx, unsigned int argc, JS::Value * vp) Line 15664 C++ xul.dll!js::InternalCallOrConstruct(JSContext * cx, const JS::CallArgs & args, js::MaybeConstruct construct) Line 448 C++ xul.dll!InternalCall(JSContext * cx, const js::AnyInvokeArgs & args) Line 493 C++ xul.dll!js::Call(JSContext * cx, JS::Handle<JS::Value> fval, JS::Handle<JS::Value> thisv, const js::AnyInvokeArgs & args, JS::MutableHandle<JS::Value> rval) Line 512 C++ xul.dll!js::Wrapper::call(JSContext * cx, JS::Handle<JSObject *> proxy, const JS::CallArgs & args) Line 165 C++ xul.dll!js::ProxyGetProperty(JSContext * cx, JS::Handle<JSObject *> proxy, JS::Handle<jsid> id, JS::MutableHandle<JS::Value> vp) Line 332 C++ [External Code]

And also this: Exception thrown at 0x7634A882 (KernelBase.dll) in firefox.exe: 0x800706BA: The RPC server is unavailable. > KernelBase.dll!7634a882() Unknown [Frames below may be incorrect and/or missing, no symbols loaded for KernelBase.dll] [External Code] FsDomSrv.dll!621615c9() Unknown FsDomNodeFirefox.dll!66297dd3() Unknown [External Code] jhook.dll!65d21f55() Unknown [External Code] FsDomSrv.dll!621bead5() Unknown [External Code] FsDomSrv.dll!621bf048() Unknown FsDomSrv.dll!621bf05a() Unknown FsDomSrv.dll!62162f50() Unknown [External Code]

Each time we see a new exception code, we should file a new bug.

Done, opened bug 1348043 and bug 1348045. This can be resolved I guess.