diff --git a/src/ops.c b/src/ops.c
index 983d9d0..35f2d2e 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -3885,7 +3885,11 @@
 		if (dir == FORWARD)
 		    curbuf->b_op_start.lnum++;
 	    }
-	    mark_adjust(curbuf->b_op_start.lnum + (y_type == MCHAR),
+	    /* Skip mark_adjust when adding lines after the last one, there
+	     * can't be marks there. */
+	    if (curbuf->b_op_start.lnum + (y_type == MCHAR) - 1 + nr_lines
+						 < curbuf->b_ml.ml_line_count)
+		mark_adjust(curbuf->b_op_start.lnum + (y_type == MCHAR),
 					     (linenr_T)MAXLNUM, nr_lines, 0L);
 
 	    /* note changed text for displaying and folding */