"An unexpected error has occurred" when trying to view/editing PowerPoint in the browser.



Receive error message "An unexpected error has occurred" when trying to view/editing PowerPoint in the browser using Office Web Apps 2010.


*  Word and Excel files are displayed without an error.




* The installation procedure for Office Web Apps did not complete successfully or an update was applied to the web app.  (The Configuration Wizard had not been executed on all servers in the farm).




*  There are missing lines in web.config file for the Web Application under the <appSettings> section.


If you take a ULS trace, you may see something like this:


Office Web Apps PowerPoint Front End f9zy Assert Unexpected exception on PptWebControl.OnInit: System.TypeInitializationException: The type initializer for 'Microsoft.Office.Server.Powerpoint.Pipe.Interface.PipeManager' threw an exception. ---> System.NotSupportedException: Specified method is not supported.




Run PSConfig on all servers in the farm.




Update any missing lines in the web.config file. 


Example <appSettings> section:



    <add key="PptServer_Pipe" value="Microsoft.Office.Server.Powerpoint.Pipe.Web.WacPipe, Microsoft.Office.Server.Powerpoint.Pipe.Web, Version=,

Culture=neutral, PublicKeyToken=71e9bce111e9429c" />

    <add key="PptServer_BroadcastManager" value="Microsoft.Office.Server.Powerpoint.Web.MossHost.MossBroadcastManager,

Microsoft.Office.Server.Powerpoint.Web.MossHost, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c" />

    <add key="FeedCacheTime" value="300" />

    <add key="FeedPageUrl" value="/_layouts/feed.aspx?" />

    <add key="FeedXsl1" value="/Style Library/Xsl Style Sheets/Rss.xsl" />

    <add key="ReportViewerMessages" value="Microsoft.SharePoint.Portal.Analytics.UI.ReportViewerMessages, Microsoft.SharePoint.Portal, Version=,

Culture=neutral, PublicKeyToken=71e9bce111e9429c" />

    <add key="aspnet:AllowAnonymousImpersonation" value="true" />

    <add key="aspnet:UseStrictParserRegex" value="true" />

    <add key="ChartImageHandler" value="storage=session;timeout=20;" />


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