Raymond Chen, a Microsoft veteran, advises against installing multiple antivirus solutions on the same system due to conflicts that arise, such as each program attempting to quarantine the other's processes. This can lead to significant performance issues and erratic behavior in Windows. Microsoft has stated that Windows Defender is sufficient for most users, highlighting its comprehensive security features in Windows 11. The company warns that running multiple real-time antivirus programs can increase resource consumption and conflict likelihood. Independent testing has shown that Microsoft Defender ranks highly among antivirus solutions.