30-year Microsoft veteran explains why you shouldn't run two antivirus apps on Windows 11

Raymond Chen, a Microsoft veteran of over three decades, says running two antivirus programs on one system causes conflicts, with each quarantining the other's processes. He notes that antivirus tools detour system functions, leading to hangs and performance issues. Microsoft has previously called Defender sufficient for most users.

• Two antivirus apps on Windows 11 quarantine each other's processes
• Antivirus detours of system functions cause hangs and slowdowns
• Microsoft called Defender enough for most users
• AV-Test scores Defender protection at 98.5–100%