When Windows Defender cannot be opened or updated, you can follow the following steps to troubleshoot: 1. Check and uninstall other security software to avoid conflicts; 2. Run the built-in "Windows Security Center" troubleshooting tool for the system; 3. Update the system and virus definition library, and reset the Defender component through PowerShell if necessary; 4. Use the sfc /scannow command to repair system file integrity. Try the above method in turn and pay attention to the operation details. Most problems can be solved.

Windows Defender is a security protection tool that comes with Windows systems, but sometimes it may not be opened or cannot be updated normally, which can be a little worried. When encountering this situation, don’t rush to reinstall the system or download third-party antivirus software. In fact, many problems can be solved through simple investigation.

The following are some common reasons and corresponding treatment methods, suitable for ordinary users:

1. Check for other security software conflicts

Windows Defender is enabled on the system by default, but if you install other antivirus software (such as Kaspersky, Turfur, 360, etc.), they may "take over" the system's security features, causing Defender to be automatically disabled.

You can check this way:

• Open Task Manager → Switch to the "Startup" tab → Check if there are any third-party antivirus software to start with the system
• Go to "Settings" → "Apps" → "Apps and Features" to see if other security software is installed

Suggested practices:

• If you plan to use Windows Defender, you can consider uninstalling other antivirus software
• After uninstalling, restart the computer, then open Defender to see if it returns to normal

2. Use the built-in troubleshooting tool for the system

Windows comes with a tool designed for detecting and fixing system problems, and sometimes it can automatically identify the abnormal state of Defender.

The operation steps are as follows:

• Open Settings → System → Troubleshooting
• Locate Windows Security Center in the Get and Run Additional Troubleshooting section
• Click "Run" to automatically scan for problems

Although this tool cannot solve all problems, it is very effective for some minor problems. If you find an error message, you can follow the prompts to search for the solution further.

3. Update the system and virus definition library

The Defender update fails, often because the system itself is not updated in place, or the virus database download is interrupted.

Try the following steps:

• Go to Settings → Windows Update → Check and install the latest system updates
• Open Settings → "Update and Security" → "Windows Security Center" → "Virus Protection" → Manually update the virus definition
• If the update fails, you can try resetting the Defender component:
  • Open PowerShell (run as administrator)
  • Enter the command: Get-MpComputerStatus to view the current status
  • Then run: Set-MpPreference -DisableRealtimeMonitoring $false

Sometimes network instability can lead to update failure. You can try changing the time period or temporarily switch the network environment (such as changing from the company network to home Wi-Fi).

4. Check system file integrity

If none of the above methods are useful, it may be that the system file is damaged, so you can use the system file checking tool to repair it.

Specific operations:

• Open a command prompt (administrator permissions)
• Enter the command: sfc /scannow
• Wait for the scan to complete, if there are any corrupt files, they will be automatically repaired

This process may take several minutes, and after completion, restart the computer and try to turn on Defender again.

Basically these common ways of dealing with it. In most cases, the problem can be solved through one or two of these steps. If you accidentally change the settings or delete some components by mistake, you can also consider using the system restore point to roll back. The whole process is not complicated, but it is easy to ignore details, such as forgetting to close third-party software or not restarting the computer. Take your time and investigate step by step, and it can usually be done.

The above is the detailed content of Windows Defender not opening or updating properly. For more information, please follow other related articles on the PHP Chinese website!