title: Getting error on Content Editor after upgrading to Sitecore 8
body: <p>I have done an upgrade from <strong>Sitecore 7.5</strong> to <strong>Sitecore 8</strong>, And I am getting <strong>an error</strong> when trying to Access the Content Editor.</p>
  
  <blockquote>
    <p>Server Error in '/' Application.</p>
    
    <p>Value cannot be null.</p>
    
    <p>Parameter name: fieldNameTranslator</p>
    
    <p><strong>Description:</strong> An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more
    information about the error and where it originated in the code. 
    Exception Details: System.ArgumentNullException: Value cannot be null.
    Parameter name: fieldNameTranslator</p>
    
    <p><strong>Source Error:</strong>  An unhandled exception was generated during the execution of the current web request. Information regarding the origin
    and location of the exception can be identified using the exception
    stack trace below.</p>
    
    <p>[ArgumentNullException: Value cannot be null.
    Parameter name: fieldNameTranslator]
    Sitecore.ContentSearch.Linq.Solr.SolrIndexParameters..ctor(IIndexValueFormatter >valueFormatter, IFieldQueryTranslatorMap`1 fieldQueryTranslators, >FieldNameTranslator fieldNameTranslator, IExecutionContext[] executionContexts, >IFieldMapReaders fieldMap, Boolean convertQueryDatesToUtc) +310</p>
    
    <blockquote>
      <p>Sitecore.ContentSearch.SolrProvider.LinqToSolrIndex`1..ctor(SolrSearchContext >context, IExecutionContext[] executionContexts) +192
      Sitecore.ContentSearch.SolrProvider.SolrSearchContext.GetQueryable(IExecutionCo>ntext[] executionContexts) +83
        Sitecore.ContentTesting.ContentSearch.TestingSearch.GetRunningTests() +637
       Sitecore.ContentTesting.Data.SitecoreContentTestStore.GetActiveTests(DataUri >hostItemDataUri, String searchText) +252
      Sitecore.ContentTesting.Pipelines.GetContentEditorWarnings.GetContentTestingWar>nings.Process(GetContentEditorWarningsArgs args) +247
        (Object , Object[] ) +141
        Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +365
        Sitecore.Shell.Applications.ContentManager.Editor.GetWarnings(Boolean >hasSections) +271
      Sitecore.Shell.Applications.ContentManager.Editor.Render(RenderContentEditorArg>s args, Control parent) +178
      Sitecore.Shell.Applications.ContentManager.ContentEditorForm.RenderEditor(Item >item, Item root, Control parent, Boolean showEditor) +231
      Sitecore.Shell.Applications.ContentManager.ContentEditorForm.UpdateEditor(Item >folder, Item root, Boolean showEditor) +374
        Sitecore.Shell.Applications.ContentManager.ContentEditorForm.Update() +411
      Sitecore.Shell.Applications.ContentManager.ContentEditorForm.OnPreRendered(Even>tArgs e) +212</p>
    </blockquote>
  </blockquote>