Suspicious or Concerning "Windows Defender Security Warning" Pop-Up/Alert




While browsing online a pop-up/alert suddenly appears indicating the computer/device has been infected or that a threat has been detected. The pop-up/alert instructs the user to call Windows technical support using a provided phone number. It may also instruct the user to not shut down/restart the computer/device. The language and appearance of the pop-up/alert will suggest a high level of urgency.


  • Do not call the provided phone number
  • Avoid interacting with the pop-up/alert directly (don't click any of the options or links)
  • If the mouse/cursor appears to be locked in place, press the ESC key on the keyboard to unlock the mouse/cursor
  • Hover over the icon for the browser and close the window or right-click on the browser icon and select the option to Close all windows (or Quit on Macs)
  • If the mouse/cursor remains locked or the browser is not closing, force shutdown/restart the device by holding the power button down

Note: If you allowed remote control to a U-M owned computer, please report the incident to  or contact the ITS Service Center.

Additional Information

Microsoft Resource on Tech Support Scams

Safe Computing has the following resources about staying safe online:

Need additional information or assistance? Contact the ITS Service Center.


Article ID: 8406
Fri 7/8/22 7:02 PM
Sat 1/6/24 11:01 AM