I have used the above already, but to no avail. I've even tried by setting IsGroupByColumn to false. But still getting the same issue.

Hello Rimi,

You may need to reset the columns, rows and bands.  For example:

UltraWebGrid1.ResetBands()

UltraWebGrid1.ResetColumns()

UltraWebGrid1.ResetRows()

Here you go, Neha:

Normal 0 false false false EN-GB X-NONE X-NONE

at System.Web.HttpAsyncResult.End()     at System.Web.UI.Page.AspCompatEndProcessRequest(IAsyncResult result)     at ASP.ngrid_xml_grid_page_aspx.EndProcessRequest(IAsyncResult ar)     at System.Web.HttpApplication.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar)--- InnerException : System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.InvalidOperationException: Failed to compare two elements in the array. ---> System.NullReferenceException: Object reference not set to an instance of an object.     at Infragistics.WebUI.UltraWebGrid.UltraGridLayout.GroupByColumnComparer.Compare(Object x, Object y)     at System.Array.BinarySearch(Array array, Int32 index, Int32 length, Object value, IComparer comparer)     --- End of inner exception stack trace ---     at System.Array.BinarySearch(Array array, Int32 index, Int32 length, Object value, IComparer comparer)     at System.Collections.SortedList.IndexOfKey(Object key)     at System.Collections.SortedList.get_Item(Object key)     at Infragistics.WebUI.UltraWebGrid.UltraGridLayout.RegisterGroupByColumn(UltraGridColumn groupedColumn)     at Infragistics.WebUI.UltraWebGrid.UltraWebGrid.GroupRows(RowsCollection rows, UltraGridColumn column)     at Infragistics.WebUI.UltraWebGrid.UltraWebGrid.SortGroupRows(RowsCollection rows)     at Infragistics.WebUI.UltraWebGrid.UltraWebGrid.PerformGroupRows()     at Infragistics.WebUI.UltraWebGrid.UltraWebGrid.PreRenderGrid()     at Infragistics.WebUI.UltraWebGrid.UltraWebGrid.OnPreRender(EventArgs e)     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)     --- End of inner exception stack trace ---     at System.Web.UI.Page.HandleError(Exception e)     at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)     at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)     at System.Web.UI.Page.ProcessRequest()     at System.Web.Util.AspCompatApplicationStep.System.Web.HttpApplication.IExecutionStep.Execute()     at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Thanks,

Rimi