Even if you have no third-party anti malware programs running on your computer, Windows Defender can sometimes behave erroneously and display an error, bearing the following message –

The Windows Defender Antivirus Network Inspection Service on Local Computer started and then stopped. Some services stop automatically if they are not in use by other services or programs.

The Windows Defender Antivirus Network Inspection Service helps guard against intrusion attempts targeting known and newly discovered vulnerabilities in network protocols.

Windows Defender Antivirus Network Inspection Service started and then stopped

Although Windows Defender offers robust security protections that you can trust, it doesn’t mean it doesn’t have issues. While starting Windows Defender Antivirus Network Inspection Service, users sometimes just can’t start the service, and hence the Windows Security app can’t be activated. To solve this issue, you can:

  1. Edit a Registry entry
  2. Use Command Prompt to start the Service.

Please note that using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows to correct them. Exercise extreme caution while using this method.

1] Edit Registry Editor entry

Press Win+R to launch the ‘Run’ dialog box, type ‘Regedit’ in the empty field provided and hit the ‘OK’ button.

Now, in the left pane of Registry Editor window, go to following path address –


Switch to the right pane of WdNisSvc folder, and look for the ‘Start’ entry.

When found, double click on the entry to modify its Value data.

Set the Value data to 3 and click OK. Close Registry Editor and restart your machine.

After restarting, see if the problem persists.

2] Use Command Prompt

In Windows 10 Search, type ‘Command Prompt’, right-click it and select ‘Run as Administrator’ option.

Now, in Command Prompt window that opens, type the following and press Enter key-

sc start WdNisSvc

If this command execution is successful, the service should be started, and you’re done.

I hope this helps!