If you have a Malwarebytes (non-real-time Anti-Malware) scanner, it's fine and can run alongside Windows Defender. However, real-time Malwarebytes Anti-Malware and Windows Defender can conflict. If you connect them without problem, the problem may be hidden or frivolous. If you having any question related to Malwarebytes not opening windows 10 you can click on the link to know about it from our experts.