Workaround: load an empty docx document in the RadRichTextEditor and use it as a template public RadDocument ImportDocx() { RadDocument document = null; IDocumentFormatProvider provider = new DocxFormatProvider(); OpenFileDialog openDialog = new OpenFileDialog(); openDialog.Filter = "Documents|*.docx"; openDialog.Multiselect = false; DialogResult dialogResult = openDialog.ShowDialog(); if (dialogResult == System.Windows.Forms.DialogResult.OK) { using (Stream stream = openDialog.OpenFile()) { document = provider.Import(stream); } } return document; }