Sign in with Microsoft
Sign in or create an account.
Select a different account.
You have multiple accounts
Choose the account you want to sign in with.


Consider the following scenario:

  • You deploy a dual tone multi-frequency (DTMF) based Interactive Voice Response (IVR) application. The application is developed by using Microsoft Lync Server 2010, Unified Communications Managed API 3.0 (UCMA3.0) Workflow Speech controls.

  • The application contains a SpeechQuestionAnswerActivity and an associated ConsecutiveNoInputsSpeechEventActivity, ConsecutiveNoRecognitionsSpeechEventActivity, SpeechHelpCommandActivity, or SpeechRepeatCommandActivity. These event or command activities contain a StatementActivity or SpeechQuestionAnswerActivity.

  • A user connects to the application, and then the user starts pressing DTMF digits while a question message plays back.

  • The application stops playing the question message and stays silent, and then the user disconnects.

In this scenario, the UCMA 3.0 workflow IVR application crashes. Additionally, you receive the following error message:

System.NullReferenceException was unhandled
Message=Object reference not set to an instance of an object.


This issue occurs because an event or command activity is initiated before the question message has completed playing. Then, internal events occur out of order and cause an unhandled runtime exception in the Windows workflow platform.


To resolve this issue, install the following update.

The following files are available for download from the Microsoft Download Center:
DownloadDownload the UcmaWorkflowRuntime.msp package now.

Release Date: April 2012

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.



Need more help?

Want more options?

Explore subscription benefits, browse training courses, learn how to secure your device, and more.

Communities help you ask and answer questions, give feedback, and hear from experts with rich knowledge.

Was this information helpful?

What affected your experience?
By pressing submit, your feedback will be used to improve Microsoft products and services. Your IT admin will be able to collect this data. Privacy Statement.

Thank you for your feedback!