I have an application that runs on a server that uses named pipes. It has run for years without a problem. This morning I came to work and was getting this error.

Access to the path is denied.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.Pipes.NamedPipeServerStream.Create(String fullPipeName, PipeDirection direction, Int32 maxNumberOfServerInstances, PipeTransmissionMode transmissionMode, PipeOptions options, Int32 inBufferSize, Int32 outBufferSize, PipeAccessRights rights, SECURITY_ATTRIBUTES secAttrs)
at System.IO.Pipes.NamedPipeServerStream..ctor(String pipeName, PipeDirection direction, Int32 maxNumberOfServerInstances, PipeTransmissionMode transmissionMode, PipeOptions options, Int32 inBufferSize, Int32 outBufferSize, PipeSecurity pipeSecurity, HandleInheritability inheritability, PipeAccessRights additionalAccessRights)
at System.IO.Pipes.NamedPipeServerStream..ctor(String pipeName, PipeDirection direction, Int32 maxNumberOfServerInstances, PipeTransmissionMode transmissionMode, PipeOptions options, Int32 inBufferSize, Int32 outBufferSize, PipeSecurity pipeSecurity)
at LRImpl.ProcComm.RSMoHelper.CreateServer()
at LRImpl.ProcComm.RSMoHelper..ctor(Boolean isServer)
at RSMoAssist.Module1.Main()

After much hand wringing we discovered that this update, kb4489893, when removed, fixed the error.

Not sure how to let Microsoft know about this.