Viewing the Activity Log for VS 2010
2009 November 1
Are you repeatedly getting a less than helpful error dialog in Visual Studio 2010?
Go to the command line and run devenv.exe with logging, reproduce the error in the IDE and then open ActivityLog.xml:

C:\>cd "C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE" C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE>devenv /Log C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE>cd %APPDATA% C:\Documents and Settings\username\Application Data>cd "Microsoft\VisualStudio\10.0" C:\Documents and Settings\username\Application Data\Microsoft\VisualStudio\10.0>dir ActivityLog.xml /B ActivityLog.xml C:\Documents and Settings\username\Application Data\Microsoft\VisualStudio\10.0>notepad ActivityLog.xml
Look for entries with type=Error, e.g.
<entry> <record>263</record> <time>2009/10/24 22:50:09.218</time> <type>Error</type> <source>Editor or Editor Extension</source> <description>System.NullReferenceException: Object reference not set to an instance of an object. at Microsoft.VisualStudio.Editor.Implementation.VsFontsAndColorsInformation.GetEditorFontForItem(IVsColorTable colorTable, Int32 itemIndex, FONTCOLORPREFERENCES2 fontColorPreferences) at Microsoft.VisualStudio.Editor.Implementation.VsFontsAndColorsInformation.TryGetItemValue(String itemKey, ResourceDictionary& itemValue) at Microsoft.VisualStudio.Text.Classification.Implementation.EditorFormatMap.CreateResourceDictionaryFromProvision(String key) at Microsoft.VisualStudio.Text.Classification.Implementation.EditorFormatMap.GetProperties(String key) at Microsoft.VisualStudio.Text.Classification.Implementation.ClassificationFormatMap.GetDefaultProperties() at Microsoft.VisualStudio.Text.Classification.Implementation.ClassificationFormatMap..ctor(ICollection`1 formats, IClassificationTypeRegistryService classificationTypeRegistry, IEditorFormatMap formatMap) at Microsoft.VisualStudio.Text.Classification.Implementation.ClassificationFormatMapService.GetClassificationFormatMap(String category) at Microsoft.VisualStudio.Text.Classification.Implementation.ViewSpecificFormatMap.AttachToFormatMaps() at Microsoft.VisualStudio.Text.Classification.Implementation.ViewSpecificFormatMap..ctor(IClassificationFormatMapService classificationFormatMapService, IEditorFormatMapService editorFormatMapService, ITextView textView) at Microsoft.VisualStudio.Text.Classification.Implementation.EditorFormatMapService.<>c__DisplayClass1.<GetEditorFormatMap>b__0() at Microsoft.VisualStudio.Utilities.PropertyCollection.GetOrCreateSingletonProperty[T](Object key, Func`1 creator) at Microsoft.VisualStudio.Text.Classification.Implementation.EditorFormatMapService.GetEditorFormatMap(ITextView textView) at Microsoft.VisualStudio.Text.Editor.Implementation.OutliningAdornmentManagerFactory.CreateTagger[T](ITextView textView, ITextBuffer buffer) at Microsoft.VisualStudio.Text.Tagging.Implementation.TagAggregator`1.GatherTaggers(ITextBuffer textBuffer)</description> </entry>
how to fix this error?
I don’t remember now. I think I had to uninstall a corrupt plug in.