System.PlatformNotSupportedException: Speech Recognition is not available on this system. SAPI and Speech Recognition engines cannot be found

Question

I am running Windows 7 Professional 64-bit with visual Studio 2010.

I have installed the Microsoft Speech Platform - Server Runtime v10.2 and the en-US language packages.

I created a Web Service (Web Application) using Microsoft.Speech. In my test the Web Service receives a string and simulates the recognition based on some grammar rules.

When I run it in Visual Studio using the ASP.NET Development Server, it works correctly without problems.

I then go to IIs and create a Virtual directory pointing to it. When I try to call the web method I get this error:

System.PlatformNotSupportedException: Speech Recognition is not available on this system. SAPI and Speech Recognition engines cannot be found.
   at Microsoft.Speech.Internal.SapiInterop.SapiRecognizer..ctor(RecognizerType type)
   at Microsoft.Speech.Recognition.SpeechRecognitionEngine.Initialize(RecognizerInfo recognizerInfo)
   at Microsoft.Speech.Recognition.SpeechRecognitionEngine..ctor(CultureInfo culture)
   at VoiceCommand.SimulateVoiceCommand(String command) in c:\Development\Visual Studio 2010\VoiceCommandWebService\VoiceCommandWS\App_Code\VoiceCommand.cs:line 35

I don't know what is the difference since I am running it in the same machine. Could it be a permissions issue?

Answer 1

I got some feedback from a Microsoft Forum.

When using the Microsoft Speech Platform - Server Runtime it will run properly in a development client OS like Windows 7, but to run it in a production setting it needs to be in a Windows Server OS.

I tested the same Web Service in Windows Server 2008 and it worked.