Published Apr 27, 2011 | Updated Sep 15, 2017


Detected by Microsoft Defender Antivirus

Aliases: TR/Ransom.Ag.qd.1 (Avira) Trojan.Winlock.3314 (Dr.Web) TROJ_ZKRYPT.SMIH (Trend Micro)


Microsoft security software detects and removes this threat.

This trojan stops you from using your PC by showing an alert message screen. This screen can include adult content and might ask you to pay a "fine" or fee to unlock your PC.

This threat also replaces important Windows system files with copies of itself.

Due to the damage this threat can do to your PC, you might need to reinstall some files from a Windows installation disc, or a backup source.

Windows 10 protects you from ransomware. Read more:

Windows 10 Creators Update provides next-gen ransomware protection

Microsoft doesn’t recommend you pay the fine. There is no guarantee that paying the ransom will give you access to your files.

If you've already paid, see our ransomware page for help on what to do now.

Run antivirus or antimalware software

The following free Microsoft software detects and removes this threat:

Even if we've already detected and removed this particular threat, running a full scan might find other malware that is hiding on your PC.

Advanced troubleshooting

To restore your PC, you might need to download and run Windows Defender Offline. See our advanced troubleshooting page for more help.

You can also ask for help from other PC users at the Microsoft virus and malware community.

If you’re using Windows XP, see our Windows XP end of support page.

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