Some spyware protection is better than none, and it’s built in and free! But… if you are already running something that provides great anti-malware protection, defender will probably wasting precious resources, there’s no need to have more than one application running at a time. It’s a small piece of software that runs in the background to help protect ,your computer from malware (malicious software) like viruses, spyware, and other potentially unwanted software. Since Vista,Microsoft Defender is included with Windows.