10 Tips to Fix Windows Defender Won’t Scan on Windows 10/11 [MiniTool Tips]

An antivirus program is essential for your computer’s security. Windows 10 and Windows 11 have the built-in free antivirus named Windows Defender. It can help protect your system from various threats.

If Windows Defender is not scanning anymore on your PC, you can try the 10 tips below to see if they can help fix Windows Defender won’t scan issue on Windows 10/11. A simple guide for how to scan with Windows Defender is also offered.

10 Tips to Fix Windows Defender Won’t Scan in Windows 10/11

Tip 1. Restart your computer and try to run a quick scan, full scan, or custom scan again with Windows Defender to see if it works properly. Many minor issues on Windows can be fixed by a simple computer restart.

Tip 2. Reset the Windows Defender app.

You can try to reset the Windows Defender app settings to default to see if it can bring the Windows Defender scan back to normal.

• Press Windows + S to open the Windows Search box.
• Type Windows Security in the search box. Right-click Windows Security App and select App settings.
• Click the Reset button under the Reset section to reset Windows Security app in Windows 11/10.

Tip 3. Check if any third-party antivirus is running in the background.

If you have installed any third-party antivirus program on your PC, it may cause conflicts with Windows Defender and cause the Windows Defender won’t scan issue. You can close, disable, or remove your third-party antivirus software to see if it helps.

To check if there is an antivirus program running in the background, you can press Ctrl + Shift + Esc to open Task Manager to check the running processes in the background on your computer. To force close a program like closing the third-party antivirus software, you can right-click the target app and select End task.

To uninstall an antivirus program on your PC, you can press Windows + R, type control panel, and press Enter to open Control Panel. Right-click the target program and select Uninstall to easily remove it from your computer.

Tip 4. Update Windows 10/11 to the latest version.

If Windows Defender can’t scan, your computer may miss some updates. You can update Windows 10/11 to install the latest updates for your system. After you update OS to the latest version, you can try to scan with Microsoft Defender again to see if it works.

Tip 5. Check for the virus on your computer.

Some viruses may crash the Windows Defender app and your system. You can run a virus scan for your PC. If Windows Defender is unable to scan, you can use a third-party antivirus app to scan your computer for malware or virus infection and remove any detected malware or virus.

Tip 6. Check the Windows Defender exclusions list.

If Windows Defender is unable to complete the quick scan, you can check the exclusions list and remove any suspicious exclusions.

• Press Windows + I to open Windows Settings.
• Click Update & Security on Windows 10 or click Privacy & Security on Windows 11.
• Click Windows Security and click Open Windows Security.
• Select Virus & threat protection.
• Click Virus & threat protection settings and locate the Exclusions Click Add or remove exclusions. If you see your system drive is on the list, you should remove it. Some malware or viruses may include your system drive to the Exclusions list and make it not found and protected by Windows Defender.

Tip 7. Perform a system scan.

You can conduct a system scan to see if it helps fix the Windows Defender scan not working issue.

• You can press Windows + R, type cmd, and press Ctrl + Shift + Enter to open Command Prompt (Admin).
• Type DISM/Online/Cleanup-Image/RestoreHealth command and press Enter.
• Type sfc /scannow command and press Enter. The SFC (System File Checker) tool will start scanning your system and fix any possible corrupted system files.

Tip 8. Use a third-party antivirus program.

If Windows Defender still can’t work properly on your PC, you can disable Windows Defender and turn to another third-party Windows security application. The best free antivirus for Windows 11/10 includes Avast Antivirus, McAfee Antivirus, Bitdefender Antivirus, etc.

Tip 9. Run a System Restore.

To fix Windows Defender won’t scan on Windows 10/11, you can also perform a system restore to revert your computer to an earlier state. You should back up all your important data before you run the system restore. Still, you can run the system restore only if you have created some system restore points before.

Tip 10. Contact the official Microsoft Support service to ask for help.

How to Scan with Microsoft Defender Antivirus on Windows 11/10

Step 1. Click the Windows Defender icon on the taskbar to open Windows Defender on Windows 10/11. If you don’t see the icon, you can also find Windows Defender or Windows Security from the Start menu or through Windows Search.

Step 2. Click Virus & threat protection. Click the Quick scan button to run a quick scan. The Quick Scan mode of Windows Defender only checks the startup folders and the registry for viruses.

If you want, you can click the Scan options link to view all scanning options of Microsoft Defender. Aside from Quick Scan, you can also see three other scanning modes: Full Scan, Custom Scan, and Microsoft Defender Offline Scan. You can choose a preferred mode and click Scan now button to instantly start the scan.

Full Scan will scan all files and running programs on your hard disk including the registry, all startup items, network-attached drives, etc. The full scan may take a few hours depending on your computer storage and speed.

Custom Scan lets you choose any file, folder, or location to scan.

Microsoft Defender Offline Scan can be used when the malware or virus is difficult to remove when the OS is active. The offline scan of Microsoft Defender can scan your computer for malware/virus before the operating system loads. Some malware may write itself in a place on your computer to protect itself and your antivirus program may not be able to delete it. Microsoft Defender Offline Scan gives a chance for your antivirus software to remove the malware.

If Windows Defender detects any malware, it will suggest ways to solve the problem. You can follow the suggestions.

How to Scan a Single File or Folder with Microsoft Defender

If you want to scan a single file or folder with Microsoft Defender instead of running a quick/full scan, you can check how to do it below.

• Click Start -> Settings -> Update & Security -> Windows Security.
• Click Virus & threat protection and click Scan options.
• Choose Custom scan and click Scan now button.
• In the pop-up Select Folder window, you can choose the folder you want to check. You won’t see single files in the window, but you can choose the folder or location which contains the target file. After selection, click the Select Folder button and the scanning will automatically start.

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How to Recover Deleted/Lost Files on Windows 10/11 for Free

If you lost some important data on your computer due to malware/virus infection, hard drive error, computer system problems, etc. you may try a professional data recovery program to see if it can help you restore lost data.

MiniTool Power Data Recovery is a top data recovery program for Windows. You can use it to recover data from various data loss situations. You can use this application to recover any deleted/lost files from Windows computers, USB flash drives, memory cards, external hard drives, SSDs, etc.

Download and install MiniTool Power Data Recovery on your Windows PC or laptop. Check the simple data recovery guide below.

Free Download

• Launch MiniTool Power Data Recovery.
• Choose the target drive under Logical Drives and click Scan. To scan the whole disk/device, you can click the Devices tab, choose the target disk or device and click Scan.
• When it finishes the scan, you can check the scan result to find if your deleted/lost files are there, if so, check them and click the Save Choose a new destination to store the recovered files.

Free PC Backup Software for Windows 10/11

To avoid permanent data loss on your computer like the data loss due to malware/virus infection, you can use a professional PC backup software program to back up your computer data and system.

MiniTool ShadowMaker is a professional free PC backup software that aims to help you back up Windows operating system and data.

It lets you easily backup and restore Windows OS.

Still, you can use MiniTool ShadowMaker to select files, folders, or partitions to back up to an external hard drive, USB flash drive, or network drive. It offers a fast backup speed for large files.

Other backup features like File Sync, Automatic Backup, Incremental Backup, etc. are also provided.

Free Download

Free Disk Partition Manager for Windows 10/11

For Windows Computer users, a top free disk partition manager is also a good helper.

MiniTool Partition Wizard is a professional disk partition manager for Windows. You can use it to easily manage hard drives by yourself from all aspects.

It lets you create, delete, extend, resize, split, merge, format, wipe, convert partitions, etc.

This full-featured disk partition manager also lets you migrate OS to SSD/HD, clone disk, test hard drive speed, analyze hard drive space, and more.

Free Download

Bottom Line

This post provides 10 tips to help you fix Windows Defender won’t scan issue on Windows 10/11. It also teaches you how to scan with Windows Defender and how to scan a single file or folder by using Microsoft Defender.

Some useful free computer software programs from MiniTool are also provided to help you with data backup and recovery and disk partition management. Hope it helps. If you have any problems with using MiniTool Software products, you can contact [email protected].