diff --git a/simple_backup/simple_backup.py b/simple_backup/simple_backup.py
index 77df8dd..3d9420e 100755
--- a/simple_backup/simple_backup.py
+++ b/simple_backup/simple_backup.py
@@ -587,7 +587,11 @@ class Backup:
                     logger.error(output)
 
         if self.keep != -1 and not self._remove_before:
-            self.remove_old_backups()
+            # Don't delete old backups if the new one may be incomplete
+            if returncode in [0, 24]:
+                self.remove_old_backups()
+            else:
+                logger.warning('Backup not completed successfully. Old backups will not be removed')
 
         os.remove(self._inputs_path)
         os.remove(self._exclude_path)