Windows
Windows Defender-style lock screen with call-back number
Windows Defender was showing a lockout-style message telling the user the computer was locked down and to call a number. The technician removed malware instances from the PC and marked the issue resolved.
Killed once by someone from XL.net, on 2026-01-30.
Affects
Apps
- Windows Defender
What you see
- Windows Defender shows a message saying the computer is locked down and tells the user to call a number.
Why it happens
Likely Suspected adware or malware produced a fake Windows Defender lockout prompt. The exact entry point was not established.
When it shows up
A Windows Defender-branded warning says the computer is locked down and prompts the user to call a phone number.
You are in this case if:
- A full-screen or alert-style Windows Defender message with a call-back number.
- The message claims the computer is locked down rather than showing a normal Defender scan or remediation screen.
1 fix below
The steps that killed it
The steps are behind a quick check
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Someone from XL.net killed this on a Windows computer on 2026-01-30. It is written up from that one repair, so it cites no outside page.