Having just upgraded a site from 6.1.1 to 6.1.3 it all works great on my dev VM. However, on the live server, when I open the Developer section in the CMS I get a javascript alert with this in it (I've set customErrors to Off in web.config):-

"error: {"Message":"An error has occurred.","ExceptionMessage":"The 'ObjectContent1' type failed to serialize the response body for content type 'application/json; charset=utf-8'.","ExceptionType":"System.InvalidOperationException","StackTrace":null,"InnerException":{"Message":"An error has occurred.","ExceptionMessage":"Could not create an index searcher with the supplied lucene directory","ExceptionType":"System.ApplicationException","StackTrace":" at Examine.LuceneEngine.Providers.LuceneSearcher.ValidateSearcher(Boolean forceReopen)\r\n at Examine.LuceneEngine.Providers.LuceneSearcher.GetSearcher()\r\n at Umbraco.Web.Search.ExamineExtensions.GetIndexReaderForSearcher(BaseLuceneSearcher searcher)\r\n at Umbraco.Web.Search.ExamineExtensions.GetIndexDocumentCount(LuceneIndexer indexer)\r\n at Umbraco.Web.WebServices.ExamineManagementApiController.CreateModel(BaseIndexProvider indexer)\r\n at System.Linq.Enumerable.WhereSelectEnumerableIterator2.MoveNext()\r\n at System.Collections.Generic.List1..ctor(IEnumerable1 collection)\r\n at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)\r\n at Newtonsoft.Json.Serialization.JsonArrayContract.CreateWrapper(Object list)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value)\r\n at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value)\r\n at System.Net.Http.Formatting.JsonMediaTypeFormatter.<>cDisplayClassd.c()\r\n at System.Threading.Tasks.TaskHelpers.RunSynchronously(Action action, CancellationToken token)","InnerException":{"Message":"An error has occurred.","ExceptionMessage":"read past EOF","ExceptionType":"System.IO.IOException","StackTrace":" at Lucene.Net.Index.SegmentInfos.FindSegmentsFile.Run(IndexCommit commit)\r\n at Lucene.Net.Index.DirectoryReader.Open(Directory directory, IndexDeletionPolicy deletionPolicy, IndexCommit commit, Boolean readOnly, Int32 termInfosIndexDivisor)\r\n at Lucene.Net.Search.IndexSearcher..ctor(Directory path, Boolean readOnly)\r\n at Examine.LuceneEngine.Providers.LuceneSearcher.ValidateSearcher(Boolean forceReopen)"}}"

I'm on shared hosting with a Plesk control panel. Have set all the directory permissions as usual. It's an MVC based site.

Any clues would be appreciated.

Cheers,

Craig