To reproduce: run the attached sample project and press the "stream export" button. Workaround: use the GridViewSpreadExport https://docs.telerik.com/devtools/winforms/gridview/exporting-data/spread-export Dim spreadExporter As GridViewSpreadExport = New GridViewSpreadExport(RadGridView1) Dim exportRenderer As New SpreadExportRenderer() Dim fileName As String = "..\..\Export" & DateTime.Now.ToLongTimeString().Replace(":", "_") + ".xlsx" spreadExporter.RunExport(fileName, exportRenderer)