If an online scan does not run, users get an error message. Here are the best troubleshooting tips for resolving the online antivirus scan failure issue.
- Antivirus scans are a necessary evil.
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Run an SFC scan
- Press Windows + S to open the Search menu, type cmd in the text field, and click on the relevant search result.
- Right-click Command prompt, and go to Run as Administrator.
- In the Command prompt window, enter sfc/scannow in the text field, and hit the Enter key.
- Wait until the scan finishes, and restart your computer.
- Run a DISM scan
Press Windows + S, type cmd in the text field, and click on the relevant search result. - Right-click Command prompt, and click on Run as Administrator.
- In the Command prompt window, enter dism/online/cleanup-image /RestoreHealth in the text field, and hit the Enter key.
- Wait until the scan finishes, and restart your computer.
- Run a DISM scan with System File Checker
Press Windows + S, type cmd in the text field, and click on the relevant search result. - Right-click Command prompt, and click on Run as Administrator.
- In the Command prompt window, enter dism/online/cleanup-image /RestoreHealth /CheckHealth in the text field, and hit the Enter key.
- Wait until the scan finishes, and restart your computer.
Reinstall Windows Defender
- Press Windows Key + X to open the Power User Menu and select Settings.
- Choose Update & Security.
- Select Windows Security from the left pane.
- Select (left) Windows Defender Antivirus.
- Click the Uninstall button.
- Wait for the removal process to complete and try re-registering the antivirus.
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Run the DISM /Online /Cleanup-Image /RestoreHealth command
- Press Windows + I to open the Settings app, and then click on Update & Security.
- Next, click on Recovery from the left pane, and then click on the Get started button under Reset this PC.
- Click on Keep my files and click on Next.
- Click on Keep my apps and click on Next.
- Once done, click on Reset.
- Restart your computer when prompted to do so.
Perform a Repair Install
- In order to revert all changes on your operating system, you can try a repair install, which can be done through the Windows 10 installation media.
- First, insert the installation media into your PC.
- When prompted, select Repair your computer.
- Follow the instructions on the screen to complete the repair install.
Perform a System Restore
- The System Restore feature can roll back your file versions to the earlier date.
- Click the Start button.
- Type in system restore.
- Select it from the search results.
- Select the desired restore point and click Next.
- Wait until Windows finishes the restore process.
