diff --git a/fast-import.c b/fast-import.c
index a523b171e2..9b71ccc479 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1204,6 +1204,8 @@ static void load_tree(struct tree_entry *root)
 			die("Not a tree: %s", sha1_to_hex(sha1));
 		t->delta_depth = myoe->depth;
 		buf = gfi_unpack_entry(myoe, &size);
+		if (!buf)
+			die("Can't load tree %s", sha1_to_hex(sha1));
 	} else {
 		enum object_type type;
 		buf = read_sha1_file(sha1, &type, &size);