Is there something I can/should do about this VS 2013 exception?

Question

On loading my ASP.NET app/site, I get this err msg: "An exception has been encountered. This may be caused by an extension."

It then says to look in this file:

C:\Users\Clay\AppData\Roaming\Microsoft\VisualStudio\11.0\ActivityLog.xml

...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:

  <entry>
    <record>676</record>
    <time>2013/10/22 13:52:50.109</time>
    <type>Error</type>
    <source>Editor or Editor Extension</source>
    <description>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.&#x000D;&#x000A;&#x000D;&#x000A;1) The export &apos;Microsoft.VisualStudio.Shell.SVsServiceProvider&apos; is not assignable to type &apos;System.Void&apos;.&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot set import &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager.VsServiceProvider (ContractName=&quot;Microsoft.VisualStudio.Shell.SVsServiceProvider&quot;)&apos; on part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager.VsServiceProvider (ContractName=&quot;Microsoft.VisualStudio.Shell.SVsServiceProvider&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot get export &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager&quot;)&apos; from part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.RegistryManager&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot set import &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider.RegistryManager (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager&quot;)&apos; on part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider.RegistryManager (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IRegistryManager&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot get export &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider&quot;)&apos; from part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.BufferFeatureManagerProvider&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot set import &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.BufferFeatureManagerProvider (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider&quot;)&apos; on part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.BufferFeatureManagerProvider (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.IBufferFeatureManagerProvider&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot get export &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName=&quot;Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider&quot;)&apos; from part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName=&quot;Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&#x000D;&#x000A;&#x000D;&#x000A;2) The export &apos;Microsoft.VisualStudio.Web.Extensions.HTML.TagNameProvider (ContractName=&quot;Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider&quot;)&apos; is not assignable to type &apos;System.Void&apos;.&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot set import &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet.TagNameProvider (ContractName=&quot;Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider&quot;)&apos; on part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet.TagNameProvider (ContractName=&quot;Microsoft.VisualStudio.Web.Extensions.HTML.ITagNameProvider&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot get export &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider&quot;)&apos; from part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.SPASupportedTagSet&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot set import &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.TagNameProvider (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider&quot;)&apos; on part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider.TagNameProvider (ContractName=&quot;Microsoft.VisualStudio.JavaScript.Web.Extensions.Shared.ISPASupportedTagProvider&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&#x000D;&#x000A;&#x000D;&#x000A;Resulting in: Cannot get export &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName=&quot;Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider&quot;)&apos; from part &apos;Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&apos;.&#x000D;&#x000A;Element: Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider (ContractName=&quot;Microsoft.VisualStudio.Text.Tagging.IViewTaggerProvider&quot;) --&gt;  Microsoft.VisualStudio.JavaScript.Web.Extensions.Classification.SPARegionTaggerProvider&#x000D;&#x000A;&#x000D;&#x000A;   at System.ComponentModel.Composition.Hosting.CompositionServices.GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition)&#x000D;&#x000A;   at System.ComponentModel.Composition.Hosting.CatalogExportProvider.GetExportedValue(CatalogPart part, ExportDefinition export, Boolean isSharedPart)&#x000D;&#x000A;   at System.ComponentModel.Composition.Hosting.CatalogExportProvider.CatalogExport.GetExportedValueCore()&#x000D;&#x000A;   at System.ComponentModel.Composition.Primitives.Export.get_Value()&#x000D;&#x000A;   at System.ComponentModel.Composition.ExportServices.GetCastedExportedValue[T](Export export)&#x000D;&#x000A;   at System.ComponentModel.Composition.ExportServices.&lt;&gt;c__DisplayClass4`2.&lt;CreateStronglyTypedLazyOfTM&gt;b__1()&#x000D;&#x000A;   at System.Lazy`1.CreateValue()&#x000D;&#x000A;   at System.Lazy`1.LazyInitValue()&#x000D;&#x000A;   at System.Lazy`1.get_Value()&#x000D;&#x000A;   at Microsoft.VisualStudio.Text.Tagging.Implementation.TagAggregator`1.GatherTaggers(ITextBuffer textBuffer)</description>
  </entry>

Decoded error is:

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)

Answer 1

This error is often caused by a corruption in the cached metadata. Why this occurs I do not know, but clearing the cache will usually return Visual Studio to working order:

• Visual Studio 2013 is unable to open the Test Window

And then this exception will also occur when you have installed Visual Studio update 1,2,3 or 4 and have other visual studio parts (like the web tools) that were built against an older version. Upgrading them to the latest version usually also helps quite a bit:

• https://jessehouwing.net/visual-studio-update-to-webtools-20122-to-resolve/