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Clear Defender scan (protection) history

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Works with Windows 10 and 11Works with Windows Vista, XP, 7, 8, 10, 11, and Windows Server 2008 or newer.
  • Windows onlyThis script improves your privacy on Windows
  • Single actionThis page belongs to a script, containing basic changes to achieve a task.
  • Impact: High

    System Functionality / Data Loss Risk: High

    This action improves privacy with high impact when you run the recommended script.

  • Batch (batchfile)These changes use Windows system commands to update your settings.
  • Administrator rights requiredThis script requires privilege access to do the system changes
  • Fully reversible

    You can fully restore this action (revert back to the original behavior) using this website.

    The restore/revert methods provided here can help you fix issues.

Overview​

This script deletes the scan history kept by Microsoft Defender on your computer. Microsoft Defender logs detected threats but also gathers and stores data about various other files it scans 1 2. While removing this history enhances your privacy, it might decrease security, as these logs assist in monitoring threats. By eliminating traces of your system's files, activities and any threats detected, you ensure no residual data can be utilized to study or analyze your computer's activities, thus protecting your privacy.

Defender keeps a log of various details whenever it scans your computer for threats. This includes 3 4:

  • Time: The moment the threat was discovered.
  • Threat Status: The action carried out against the threat.
  • Virus Type: The type or category of the virus.
  • Threat ID: A unique identifier for the threat.
  • Virus Name: The name of the virus.
  • File Path: The location of the threat on your computer.
  • File Hash: A unique code representing the file.
  • Quarantine File Name (GUID): The name given to the quarantined threat.
  • File Size: The size of the file.

When you first set up Windows, it conducts an initial scan 1. This scan identifies system files that won't require future scans 1. These 'safe' files are saved in a unique folder, which becomes a part of the scan history 1.

If a threat is recognized, Microsoft Defender will notify you 4. Regardless of whether you choose to run the file or not, a DetectionHistory file is created 2. This file is stored in a specific folder (%ProgramData%\Microsoft\Windows Defender\Scans\History\Service\DetectionHistory\[numbered folder]\), and it contains a system-generated ID for the event 2.

Caution

Deleting these logs may decrease your security. These logs help in keeping track of potential threats and their sources, allowing for a more proactive response in future encounters. Without this history, Microsoft Defender might not recognize recurring threats allowing for a more proactive response in future encounters. Without this history, Microsoft Defender might not recognize recurring threats as quickly, possibly leaving your system more vulnerable. It's essential to understand that you're making a trade-off between enhanced as quickly, possibly leaving your system more vulnerable. It's essential to understand that you're making a trade-off between enhanced privacy and potentially reduced security. privacy and potentially reduced security.

Not Advised

This script should only be used by advanced users.

This script is not recommended for daily use as it breaks important functionality.

Consider creating a system restore point before doing any changes.

Sources
PrivacyLearn.com maintains strict sourcing standards for accuracy, integrity and up-to-date content. Our content relies on authoritative sources including vendor documentation, industry standards, and verified research. Learn more about our verification process and quality standards in our editorial standards page.

Apply Now​

Choose one of three ways to apply:

Download script​

Download and run the script directly
  • No app needed
  • Offline usage
  • Easy-to-apply
  • Free
  • Open-source
Help

How to apply or restore "Clear Defender scan (protection) history" using script​

  • ≈ 2 min to complete
  • Tools: Web Browser
  • Difficulty: Simple
  • ≈ 5 instructions
  1. 1

    Download

    Download the script file by clicking on the   Apply protection  button above.
    Use   Undo protection button above to restore changes.
  2. 2

    Keep the file

    If warned by your browser, keep the file.
  3. 3

    Open

    Open the downloaded file.
  4. 4

    Exit

    Once it's done, press any key to exit the window.
  5. 5

    Restart

    Restart your computer for all changes to take effect.

Apply with privacy.sexy​

Guided, automated application with safety checks
  • Recommended for most users
  • Includes safety checks
  • Free
  • Open-source
  • Popular
  • Offline/Online usage
Open privacy.sexy
Help

How to apply or restore "Clear Defender scan (protection) history" using privacy.sexy​

  • ≈ 3 min to complete
  • Tools: privacy.sexy
  • Difficulty: Simple
  • ≈ 4 instructions
privacy.sexy is free and open-source application that lets securely apply this action easily with more advanced options.
  1. 1

    Open or download

    Open or download the desktop application
  2. 2

    Choose script

    1. Search for the script name: Clear Defender scan (protection) history
    2. Check the script by clicking on the checkbox.
  3. 3

    Run

    Click on ▶️ Run button at the bottom of the page.

    This button only appears on desktop version (recommended). On browser, use 💾 Save button.

Run commands​

Copy and run commands manually Requires technical knowledge
Apply changes
:: Clear directory contents (with additional permissions) : "%ProgramData%\Microsoft\Windows Defender\Scans\History"
PowerShell -ExecutionPolicy Unrestricted -Command "$pathGlobPattern = "^""$($directoryGlob = '%ProgramData%\Microsoft\Windows Defender\Scans\History'; if ($directoryGlob.EndsWith('\*')) { $directoryGlob } elseif ($directoryGlob.EndsWith('\')) { "^""$($directoryGlob)*"^"" } else { "^""$($directoryGlob)\*"^"" } )"^""; $expandedPath = [System.Environment]::ExpandEnvironmentVariables($pathGlobPattern); Write-Host "^""Searching for items matching pattern: `"^""$($expandedPath)`"^""."^""; <# Not using `Get-Acl`/`Set-Acl` to avoid adjusting token privileges #>; $parentDirectory = [System.IO.Path]::GetDirectoryName($expandedPath); $fileName = [System.IO.Path]::GetFileName($expandedPath); if ($parentDirectory -like '*[*?]*') { throw "^""Unable to grant permissions to glob path parent directory: `"^""$parentDirectory`"^"", wildcards in parent directory are not supported by ``takeown`` and ``icacls``."^""; }; if (($fileName -ne '*') -and ($fileName -like '*[*?]*')) { throw "^""Unable to grant permissions to glob path file name: `"^""$fileName`"^"", wildcards in file name is not supported by ``takeown`` and ``icacls``."^""; }; Write-Host "^""Taking ownership of `"^""$expandedPath`"^""."^""; $cmdPath = $expandedPath; if ($cmdPath.EndsWith('\')) { $cmdPath += '\' <# Escape trailing backslash for correct handling in batch commands #>; }; $takeOwnershipCommand = "^""takeown /f `"^""$cmdPath`"^"" /a"^"" <# `icacls /setowner` does not succeed, so use `takeown` instead. #>; if (-not (Test-Path -Path "^""$expandedPath"^"" -PathType Leaf)) { $localizedYes = 'Y' <# Default 'Yes' flag (fallback) #>; try { $choiceOutput = cmd /c "^""choice <nul 2>nul"^""; if ($choiceOutput -and $choiceOutput.Length -ge 2) { $localizedYes = $choiceOutput[1]; } else { Write-Warning "^""Failed to determine localized 'Yes' character. Output: `"^""$choiceOutput`"^"""^""; }; } catch { Write-Warning "^""Failed to determine localized 'Yes' character. Error: $_"^""; }; $takeOwnershipCommand += "^"" /r /d $localizedYes"^""; }; $takeOwnershipOutput = cmd /c "^""$takeOwnershipCommand 2>&1"^"" <# `stderr` message is misleading, e.g. "^""ERROR: The system cannot find the file specified."^"" is not an error. #>; if ($LASTEXITCODE -eq 0) { Write-Host "^""Successfully took ownership of `"^""$expandedPath`"^"" (using ``$takeOwnershipCommand``)."^""; } else { Write-Host "^""Did not take ownership of `"^""$expandedPath`"^"" using ``$takeOwnershipCommand``, status code: $LASTEXITCODE, message: $takeOwnershipOutput."^""; <# Do not write as error or warning, because this can be due to missing path, it's handled in next command. #>; <# `takeown` exits with status code `1`, making it hard to handle missing path here. #>; }; Write-Host "^""Granting permissions for `"^""$expandedPath`"^""."^""; $adminSid = New-Object System.Security.Principal.SecurityIdentifier 'S-1-5-32-544'; $adminAccount = $adminSid.Translate([System.Security.Principal.NTAccount]); $adminAccountName = $adminAccount.Value; $grantPermissionsCommand = "^""icacls `"^""$cmdPath`"^"" /grant `"^""$($adminAccountName):F`"^"" /t"^""; $icaclsOutput = cmd /c "^""$grantPermissionsCommand"^""; if ($LASTEXITCODE -eq 3) { Write-Host "^""Skipping, no items available for deletion according to: ``$grantPermissionsCommand``."^""; exit 0; } elseif ($LASTEXITCODE -ne 0) { Write-Host "^""Take ownership message:`n$takeOwnershipOutput"^""; Write-Host "^""Grant permissions:`n$icaclsOutput"^""; Write-Warning "^""Failed to assign permissions for `"^""$expandedPath`"^"" using ``$grantPermissionsCommand``, status code: $LASTEXITCODE."^""; } else { $fileStats = $icaclsOutput | ForEach-Object { $_ -match '\d+' | Out-Null; $matches[0] } | Where-Object { $_ -ne $null } | ForEach-Object { [int]$_ }; if ($fileStats.Count -gt 0 -and ($fileStats | ForEach-Object { $_ -eq 0 } | Where-Object { $_ -eq $false }).Count -eq 0) { Write-Host "^""Skipping, no items available for deletion according to: ``$grantPermissionsCommand``."^""; exit 0; } else { Write-Host "^""Successfully granted permissions for `"^""$expandedPath`"^"" (using ``$grantPermissionsCommand``)."^""; }; }; $deletedCount = 0; $failedCount = 0; $foundAbsolutePaths = @(); Write-Host 'Iterating files and directories recursively.'; try { $foundAbsolutePaths += @(; Get-ChildItem -Path $expandedPath -Force -Recurse -ErrorAction Stop | Select-Object -ExpandProperty FullName; ); } catch [System.Management.Automation.ItemNotFoundException] { <# Swallow, do not run `Test-Path` before, it's unreliable for globs requiring extra permissions #>; }; try { $foundAbsolutePaths += @(; Get-Item -Path $expandedPath -ErrorAction Stop | Select-Object -ExpandProperty FullName; ); } catch [System.Management.Automation.ItemNotFoundException] { <# Swallow, do not run `Test-Path` before, it's unreliable for globs requiring extra permissions #>; }; $foundAbsolutePaths = $foundAbsolutePaths | Select-Object -Unique | Sort-Object -Property { $_.Length } -Descending; if (!$foundAbsolutePaths) { Write-Host 'Skipping, no items available.'; exit 0; }; Write-Host "^""Initiating processing of $($foundAbsolutePaths.Count) items from `"^""$expandedPath`"^""."^""; foreach ($path in $foundAbsolutePaths) { if (-not (Test-Path $path)) { <# Re-check existence as prior deletions might remove subsequent items (e.g., subdirectories). #>; Write-Host "^""Successfully deleted: $($path) (already deleted)."^""; $deletedCount++; continue; }; try { Remove-Item -Path $path -Force -Recurse -ErrorAction Stop; $deletedCount++; Write-Host "^""Successfully deleted: $($path)"^""; } catch { $failedCount++; Write-Warning "^""Unable to delete $($path): $_"^""; }; }; Write-Host "^""Successfully deleted $($deletedCount) items."^""; if ($failedCount -gt 0) { Write-Warning "^""Failed to delete $($failedCount) items."^""; }"
Help

How to apply or restore "Clear Defender scan (protection) history" using commands​

  • ≈ 2 min to complete
  • Tools: Command Prompt
  • Difficulty: Medium
  • ≈ 3 instructions
 View step-by-step guide with screenshots
  1. 1

    Open Command Prompt

    Open Command Prompt as Administrator.
  2. 2

    Copy code

    Copy the code:
    Copy Apply Code Copy Revert Code
  3. 3

    Paste & run

    Paste the commands into Command Prompt and press Enter to run.

    Some changes require a system restart to take effect

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About the Creators​

These people have authored this documentation and written its scripts:

  • Avatar of undergroundwires. The creator of PrivacyLearn and privacy.sexy. Black and white portrait showing a person wearing a polka dot tie and suit jacket, reflecting the professional expertise behind the privacy protection tools.
    • Certified security professional
    • 7+ years experience securing banks
    • Open-source developer since 2005
    • EU advisor, Public Speaker, Moderator
    • Hundreds across the globe
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    • Companies, military agencies
    • Community since 2017
About Us

Reviewed By​

This guide has undergone comprehensive auditing and peer review:

  • Expert review by undergroundwires​

    • Verified technical accuracy and editorial standards
    • Assessed system impact and user privacy risks

  • Public review by large community​

    • Privacy enthusiasts and professionals peer-reviewed
    • Millions of end-users tested across different environments

History​

We continually monitor our guides, their impact and all other privacy options. We update our guides when new information becomes available. On every update, we publicly store who made the change, what has been changed, why the change was made and when the change was made.

Review Change History Our Change Process