diff --git a/pds.go b/pds.go
index fbbc138..cc5c6c3 100644
--- a/pds.go
+++ b/pds.go
@@ -116,7 +116,11 @@ func (s *service) backupBlobs(ctx context.Context) error {
 		return fmt.Errorf("get all blob CIDs: %w", err)
 	}
 
-	filename := fmt.Sprintf("%s-%s-blobs.zip", s.did, time.Now())
+	if len(cids) == 0 {
+		return nil
+	}
+
+	filename := path.Join(s.blobDir, fmt.Sprintf("%s-%d-blobs.zip", s.did, time.Now().UnixMilli()))
 	defer os.Remove(filename)
 
 	f, err := os.Create(filename)