title: Is there something I can/should do about this VS 2013 exception?
body: <p>On loading my ASP.NET app/site, I get this err msg: "An exception has been encountered. This may be caused by an extension."</p>
  
  <p>It then says to look in this file:</p>
  
  <p>C:\Users\Clay\AppData\Roaming\Microsoft\VisualStudio\11.0\ActivityLog.xml</p>
  
  <p>...in which I did find three entries that may be related to the problem, yet they are "Greek to me". Due to their voluminosity, I am just including the first one here:</p>
  
  <pre><code>  &lt;entry&gt;
      &lt;record&gt;676&lt;/record&gt;
      &lt;time&gt;2013/10/22 13:52:50.109&lt;/time&gt;
      &lt;type&gt;Error&lt;/type&gt;
      &lt;source&gt;Editor or Editor Extension&lt;/source&gt;
      &lt;description&gt;System.ComponentModel.Composition.CompositionException: The composition produced a single composition error, with 2 root causes. The root causes are provided below. Review the CompositionException.Errors property for more detailed information.&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;1) The export &amp;apos;Microsoft.VisualStudio.Shell.SVsServiceProvider&amp;apos; is not assignable to type &amp;apos;System.Void&amp;apos;.&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot set import &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager.VsServiceProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Shell.SVsServiceProvider&amp;quot;)&amp;apos; on part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager.VsServiceProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Shell.SVsServiceProvider&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot get export &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager&amp;quot;)&amp;apos; from part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot set import &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider.RegistryManager (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager&amp;quot;)&amp;apos; on part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider.RegistryManager (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot get export &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider&amp;quot;)&amp;apos; from part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot set import &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.BufferFeatureManagerProvider (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider&amp;quot;)&amp;apos; on part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.BufferFeatureManagerProvider (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot get export &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider&amp;quot;)&amp;apos; from part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;2) The export &amp;apos;Microsoft.VisualStudio.Web.Extensions.HTML.TagNameProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider&amp;quot;)&amp;apos; is not assignable to type &amp;apos;System.Void&amp;apos;.&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot set import &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet.TagNameProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider&amp;quot;)&amp;apos; on part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet.TagNameProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot get export &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider&amp;quot;)&amp;apos; from part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot set import &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.TagNameProvider (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider&amp;quot;)&amp;apos; on part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.TagNameProvider (ContractName=&amp;quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;Resulting in: Cannot get export &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider&amp;quot;)&amp;apos; from part &amp;apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&amp;apos;.&amp;#x000D;&amp;#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName=&amp;quot;Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider&amp;quot;) --&amp;gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&amp;#x000D;&amp;#x000A;&amp;#x000D;&amp;#x000A;   at System.ComponentModel.Composition.Hosting.CompositionServices.GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition)&amp;#x000D;&amp;#x000A;   at System.ComponentModel.Composition.Hosting.CatalogExportProvider.GetExportedValue(CatalogPart part, ExportDefinition export, Boolean isSharedPart)&amp;#x000D;&amp;#x000A;   at System.ComponentModel.Composition.Hosting.CatalogExportProvider.CatalogExport.GetExportedValueCore()&amp;#x000D;&amp;#x000A;   at System.ComponentModel.Composition.Primitives.Export.get_Value()&amp;#x000D;&amp;#x000A;   at System.ComponentModel.Composition.ExportServices.GetCastedExportedValue[T](Export export)&amp;#x000D;&amp;#x000A;   at System.ComponentModel.Composition.ExportServices.&amp;lt;&amp;gt;c__DisplayClass4`2.&amp;lt;CreateStronglyTypedLazyOfTM&amp;gt;b__1()&amp;#x000D;&amp;#x000A;   at System.Lazy`1.CreateValue()&amp;#x000D;&amp;#x000A;   at System.Lazy`1.LazyInitValue()&amp;#x000D;&amp;#x000A;   at System.Lazy`1.get_Value()&amp;#x000D;&amp;#x000A;   at Microsoft.VisualStudio.Text.Tagging.Implementation.TagAggregator`1.GatherTaggers(ITextBuffer textBuffer)&lt;/description&gt;
    &lt;/entry&gt;
  </code></pre>
  
  <p>Decoded error is:</p>
  
  <pre>
  System.ComponentModel.Composition.CompositionException: The composition produced a single composition error, with 2 root causes. The root causes are provided below. Review the CompositionException.Errors property for more detailed information.
  
  1) The export 'Microsoft.VisualStudio.Shell.SVsServiceProvider' is not assignable to type 'System.Void'.
  
  Resulting in: Cannot set import 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager.VsServiceProvider (ContractName="Microsoft.VisualStudio.Shell.SVsServiceProvider")' on part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager.VsServiceProvider (ContractName="Microsoft.VisualStudio.Shell.SVsServiceProvider") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager
  
  Resulting in: Cannot get export 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager")' from part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager
  
  Resulting in: Cannot set import 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider.RegistryManager (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager")' on part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider.RegistryManager (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider
  
  Resulting in: Cannot get export 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider")' from part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider
  
  Resulting in: Cannot set import 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.BufferFeatureManagerProvider (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider")' on part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.BufferFeatureManagerProvider (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider
  
  Resulting in: Cannot get export 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName="Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider")' from part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName="Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider
  
  2) The export 'Microsoft.VisualStudio.Web.Extensions.HTML.TagNameProvider (ContractName="Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider")' is not assignable to type 'System.Void'.
  
  Resulting in: Cannot set import 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet.TagNameProvider (ContractName="Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider")' on part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet.TagNameProvider (ContractName="Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet
  
  Resulting in: Cannot get export 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider")' from part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet
  
  Resulting in: Cannot set import 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.TagNameProvider (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider")' on part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.TagNameProvider (ContractName="Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider
  
  Resulting in: Cannot get export 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName="Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider")' from part 'Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider'.
  Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName="Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider") -->  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider
  
     at System.ComponentModel.Composition.Hosting.CompositionServices.GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition)
     at System.ComponentModel.Composition.Hosting.CatalogExportProvider.GetExportedValue(CatalogPart part, ExportDefinition export, Boolean isSharedPart)
     at System.ComponentModel.Composition.Hosting.CatalogExportProvider.CatalogExport.GetExportedValueCore()
     at System.ComponentModel.Composition.Primitives.Export.get_Value()
     at System.ComponentModel.Composition.ExportServices.GetCastedExportedValue[T](Export export)
     at System.ComponentModel.Composition.ExportServices.c__DisplayClass4`2.b__1()
     at System.Lazy`1.CreateValue()
     at System.Lazy`1.LazyInitValue()
     at System.Lazy`1.get_Value()
     at Microsoft.VisualStudio.Text.Tagging.Implementation.TagAggregator`1.GatherTaggers(ITextBuffer textBuffer)
  </pre>