diff --git a/plugins/excel/ms-excel-read.c b/plugins/excel/ms-excel-read.c
index fb90730..559c0c0 100644
--- a/plugins/excel/ms-excel-read.c
+++ b/plugins/excel/ms-excel-read.c
@@ -5033,6 +5033,7 @@ excel_read_ITERATION (BiffQuery *q, GnmXLImporter *importer)
 static void
 excel_read_PANE (BiffQuery *q, ExcelReadSheet *esheet, WorkbookView *wb_view)
 {
+	g_return_if_fail (q->data);
 	if (esheet->freeze_panes) {
 		guint16 x = GSF_LE_GET_GUINT16 (q->data + 0);
 		guint16 y = GSF_LE_GET_GUINT16 (q->data + 2);
