Microsoft defender security locked my computer can't do anything

This is commonly a tech support scam page, especially if the screen claims Microsoft Defender found threats and the PC is “locked.” Microsoft error and warning messages never include phone numbers.

Try these steps in order:

1. Do not call any phone number shown on the screen.
2. If the message is in a browser page, press Ctrl+Alt+Del and try to close browser processes from Task Manager if it opens.
3. If Task Manager cannot be reached, press the power button once to shut down the PC, then turn it back on.
4. It is also a good idea to disconnect from the internet.
5. After getting back into Windows, run a malware check:
   • Go to Start > Settings > Update & Security > Windows Security > Virus & threat protection.
   • Under Current threats, select Scan options.
   • Select Windows Defender Offline scan and then Scan now.
   • Note: save work first, because the PC will restart before the scan.
6. If Microsoft Defender Antivirus keeps showing scan or removal errors afterward:
   • Run Windows Update.
   • If needed, install the latest protection updates manually.
7. If a threat is reported as partially removed, run the Malicious Software Removal Tool:
   • Press Windows logo key + R.
   • Type %windir%\system32\mrt.exe and select OK.
   • Approve the prompt if shown, then follow the scan and cleanup steps.
8. If malware caused lasting damage, use Reset, restore, or reinstall your PC after backing up files. Restoring from backups created before the infection is recommended.

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