Windows 11 is warning people that Defender Antivirus has been turned off, but don't worry, says Microsoft

Published Aug 29, 2026, 11:30 PM EDT Simon is a Computer Science BSc graduate who has been writing about technology since 2014, and using Windows machines since 3.1. After working for an indie game studio and acting as the family's go-to technician for all computer issues, he found his passion for writing and decided to use his skill set to write about all things tech. Since beginning his writing career, he has written for many different publications such as WorldStart, Listverse, and MakeTechEasier. However, after finding his home at MakeUseOf in February 2019, he would eventually move on to its sister site, XDA, to bring the latest and greatest in Windows, Linux, and DIY electronics. Sign in to your XDA account Summary Windows 11 may show false "Microsoft Defender Antivirus is turned off" alerts after updates. Microsoft says it's a bug; Defender remains active if settings show it on. No action needed beyond verifying Defender is on; a fix is coming soon. Windows 11's built-in security program, Microsoft Defender Antivirus, is a solid pick for keeping you safe. Best of all, it's readily installed and running the moment you boot up the OS for the first time. Which is why, if you've been getting spammed by notifications claiming that "Microsoft Defender Antivirus is turned off" when everything seems okay, it's only natural to be a little bit worried. Fortunately, Microsoft has broken the silence about this weird issue, stating that the repeated notifications are a bug and will be rectified soon. So, if you're seeing the notification pop up and you've double-checked that it's still on, you have nothing to worry about. Windows 11 is showing a "Microsoft Defender Antivirus is turned off" notification even when it's on It's a little scary, but everything is fine under the hood As spotted by Windows Latest, Microsoft has updated its documentation on known issues for Windows 11, version 25H2. A new issue has appeared titled 'Incorrect notifications that "Microsoft Defender Antivirus is turned off,"' both logged and posted on August 28th, with the following description: After installing the latest updates for Microsoft Defender Antivirus, notifications might appear stating that "Microsoft Defender Antivirus is turned off," even though the antivirus is functioning correctly and all settings show it as active. These notifications can appear when Windows starts and intermittently afterward. They persist even if notification settings are turned off. If you get this alert on your PC, first, double-check to ensure that your Microsoft Defender Antivirus isn't actually turned off. If you see that everything is turned on and working fine, you need not have to worry; the messages are a false alarm, and your computer is still working just fine.