Help Viewer 2.3 Crashing

Question

Running on Windows 11 10.0.22000.613.

The Help Viewer is crashing on both
Microsoft Visual Studio Professional 2022 (64-bit) Version 17.1.5
Microsoft Visual Studio Professional 2019 Version 16.11.13

I see this in the event logs:

Faulting application name: HlpViewer.exe, version: 2.3.32406.258, time stamp: 0xd01c5c28
Faulting module name: KERNELBASE.dll, version: 10.0.22000.613, time stamp: 0xb8da8cf0
Exception code: 0xe0434352
Fault offset: 0x0013ed42
Faulting process id: 0x3180
Faulting application start time: 0x01d855804f047057
Faulting application path: C:\Program Files (x86)\Microsoft Help Viewer\v2.3\HlpViewer.exe
Faulting module path: C:\WINDOWS\System32\KERNELBASE.dll
Report Id: 7e8955bd-dfd8-424c-ba65-2381976bd8bf
Faulting package full name:
Faulting package-relative application ID:

And this:

Application: HlpViewer.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.IO.FileLoadException
at Microsoft.VisualStudio.Help.Viewer.Application.ApplicationServiceProvider.Initialize()
at Microsoft.VisualStudio.Help.Viewer.Application.ApplicationServiceProvider..ctor()

Exception Info: System.Reflection.TargetInvocationException
at System.RuntimeTypeHandle.CreateInstance(System.RuntimeType, Boolean, Boolean, Boolean ByRef, System.RuntimeMethodHandleInternal ByRef, Boolean ByRef)
at System.RuntimeType.CreateInstanceSlow(Boolean, Boolean, Boolean, System.Threading.StackCrawlMark ByRef)
at System.RuntimeType.CreateInstanceDefaultCtor(Boolean, Boolean, Boolean, System.Threading.StackCrawlMark ByRef)
at System.Activator.CreateInstance(System.Type, Boolean)
at System.Activator.CreateInstance(System.Type)
at System.Lazy1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].CreateValue() at System.Lazy1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].LazyInitValue()
at System.Lazy`1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].get_Value()
at Microsoft.VisualStudio.Help.Viewer.App.Main(System.String[])

I've tried repairing and removing/reinstalling Help Viewer -- no difference.