Hi

Using Umbraco version 7.1.8

The Internal Index does suddenly not get indexed. It does not get indexed on startup and I cannot do a rebuild through the Examine Dashboard.

I get this error:

The index could not be rebuilt at this time, most likely there is another thread currently writing to the index. Error: System.NullReferenceException: Object reference not set to an instance of an object.
   at Umbraco.Core.Services.UserService.GetProfileById(Int32 id)
   at Umbraco.Core.Models.ContentExtensions.GetCreatorProfile(IContentBase content)
   at Umbraco.Core.Services.EntityXmlSerializer.Serialize(IContentService contentService, IDataTypeService dataTypeService, IContent content, Boolean deep)
   at Umbraco.Core.Services.EntityXmlSerializer.AddChildXml(IContentService contentService, IDataTypeService dataTypeService, IContent[] originalDescendants, IEnumerable`1 currentChildren, XElement currentXml)
   at Umbraco.Core.Services.EntityXmlSerializer.AddChildXml(IContentService contentService, IDataTypeService dataTypeService, IContent[] originalDescendants, IEnumerable`1 currentChildren, XElement currentXml)
   at Umbraco.Core.Services.EntityXmlSerializer.Serialize(IContentService contentService, IDataTypeService dataTypeService, IContent content, Boolean deep)
   at Umbraco.Core.Services.PackagingService.Export(IContent content, Boolean deep, Boolean raiseEvents)
   at Umbraco.Core.Models.ContentExtensions.ToDeepXml(IContent content)
   at UmbracoExamine.DataServices.UmbracoContentService.GetLatestContentByXPath(String xpath)
   at UmbracoExamine.BaseUmbracoIndexer.GetXDocument(String xPath, String type)
   at UmbracoExamine.BaseUmbracoIndexer.AddNodesToIndex(String xPath, String type)
   at UmbracoExamine.BaseUmbracoIndexer.PerformIndexAll(String type)
   at Examine.LuceneEngine.Providers.LuceneIndexer.IndexAll(String type) in x:\Projects\Examine\Examine\Projects\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 675
   at UmbracoExamine.BaseUmbracoIndexer.IndexAll(String type)
   at UmbracoExamine.BaseUmbracoIndexer.PerformIndexRebuild()
   at UmbracoExamine.UmbracoContentIndexer.RebuildIndex()
   at Umbraco.Web.WebServices.ExamineManagementApiController.PostRebuildIndex(String indexerName)

I have tried to remove the App_Data\Temp folder, but that did not help.

Does anybody have a clue on what I can do?

/Mikkel