diff --git a/block/qcow2.c b/block/qcow2.c
index 7fbef97aab..840f289a48 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -4384,14 +4384,17 @@ static int qcow2_make_empty(BlockDriverState *bs)
 
     if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps &&
         3 + l1_clusters <= s->refcount_block_size &&
-        s->crypt_method_header != QCOW_CRYPT_LUKS) {
+        s->crypt_method_header != QCOW_CRYPT_LUKS &&
+        !has_data_file(bs)) {
         /* The following function only works for qcow2 v3 images (it
          * requires the dirty flag) and only as long as there are no
          * features that reserve extra clusters (such as snapshots,
          * LUKS header, or persistent bitmaps), because it completely
          * empties the image.  Furthermore, the L1 table and three
          * additional clusters (image header, refcount table, one
-         * refcount block) have to fit inside one refcount block. */
+         * refcount block) have to fit inside one refcount block. It
+         * only resets the image file, i.e. does not work with an
+         * external data file. */
         return make_completely_empty(bs);
     }