I’ve been battling an issue for several days. Among our solutions, we have an aging monolith comprising various ASP.NET technologies, as well as a WCF service, and several other Windows Services. Everything builds for my colleagues, and the services all start correctly. I hadn’t worked on the monolith in a while, and when I turned my attention back to it, I experienced some various errors, including one that I still have not solved. In order for our WCF stuff to work, we have to run a Windows Service that acts as the WCF host. When I try to start this service, it bombs out, throwing up this dialog:

Windows could not start the {name of service} service on Local Computer. Error 1064: An exception occurred in the service when handling the control request.

Checking Event Viewer, I find this .NET Runtime error in Windows Logs/Application:

Application: {redacted full path/name of WCF service host}.exe Framework Version: v4.0.30319 Description: The process was terminated due to an unhandled exception. Exception Info: System.IO.FileNotFoundException  Exception Info: System.IO.FileNotFoundException    at System.ServiceModel.Channels.HttpChannelListener..ctor(System.ServiceModel.Channels.HttpTransportBindingElement, System.ServiceModel.Channels.BindingContext)    at System.ServiceModel.Channels.HttpChannelListener`1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]..ctor(System.ServiceModel.Channels.HttpTransportBindingElement, System.ServiceModel.Channels.BindingContext)    at System.ServiceModel.Channels.HttpTransportBindingElement.BuildChannelListener[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]](System.ServiceModel.Channels.BindingContext)    at System.ServiceModel.Channels.Binding.BuildChannelListener[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]](System.Uri, System.String, System.ServiceModel.Description.ListenUriMode, System.ServiceModel.Channels.BindingParameterCollection)    at System.ServiceModel.Description.ServiceMetadataExtension.CreateGetDispatcher(System.Uri, System.ServiceModel.Channels.Binding, System.String)    at System.ServiceModel.Description.ServiceMetadataExtension.EnsureGetDispatcher(System.Uri, Boolean)    at System.ServiceModel.Description.ServiceMetadataBehavior.EnsureGetDispatcher(System.ServiceModel.ServiceHostBase, System.ServiceModel.Description.ServiceMetadataExtension, System.Uri, System.String)    at System.ServiceModel.Description.ServiceMetadataBehavior.CreateHttpGetEndpoints(System.ServiceModel.Description.ServiceDescription, System.ServiceModel.ServiceHostBase, System.ServiceModel.Description.ServiceMetadataExtension)    at System.ServiceModel.Description.DispatcherBuilder.InitializeServiceHost(System.ServiceModel.Description.ServiceDescription, System.ServiceModel.ServiceHostBase)    at System.ServiceModel.ServiceHostBase.InitializeRuntime()    at System.ServiceModel.ServiceHostBase.OnOpen(System.TimeSpan)    at System.ServiceModel.Channels.CommunicationObject.Open(System.TimeSpan)    at {elided - a few more stack trace lines referring to our custom code} 

Also in the same Event Viewer log, I have this Application Error (immediately after the .NET Runtime one):

Faulting application name: {service name}.exe, version: 4.2.0.0, time stamp: 0x5f0f45ce Faulting module name: KERNELBASE.dll, version: 10.0.18362.815, time stamp: 0xb89efff3 Exception code: 0xe0434352 Fault offset: 0x000000000003a799 Faulting process id: 0xd84 Faulting application start time: 0x01d65ad32192a62b Faulting application path: {full service path/name}.exe Faulting module path: C:\WINDOWS\System32\KERNELBASE.dll Report Id: 1db8e59a-b3a0-47e3-bb0f-5d8c6e2f8ed5 Faulting package full name:  Faulting package-relative application ID:  

I’ve mostly been working in .NET Core with VS 2019 for the past year and a half, and so I thought maybe some configuration or SDK needed for Framework had gone missing. I still have 2017 on my machine, and that is what my colleagues prefer to use for this one monolithic solution. Now, over these several days, I have done the following:

• Removed and/or installed various SDKs and targeting packs
• Repaired VS 2017
• Uninstalled and reinstalled VS 2017
• Repaired VS 2019
• Uninstalled and reinstalled VS 2019
• Uninstalled and reinstalled the Windows Services many times

I’ve picked up the vaguest hints from web search results above my head that there could be a problem with some binding redirects. Initially I could have sworn I saw evidence that the FileNotFound was something in System.Net.Http, but now I can’t seem to find whatever indicated that to me. At this point I’m completely burnt on it, and I’m considering just wiping the whole system and starting with a clean Windows installation. It would be a real shame if I were to have to do that. If you have even the vaguest hint about where to look or what to try, it would be much appreciated.