Are you sure you don’t have a module/plugin installed that is doing that? I am not aware of NB auto-saving anything without a plugin installed such as “AutoSaveModified” from the plugin portal which the description says it saves every second. It may or may not be configurable; I’m not its author. If so, see the plugins home page or docs, or one sure way to solve that is to uninstall such a plugin. NB will save files before you run a test or perform certain actions though, but it sounded like that wasn’t what you were referring to.