Control maximum size of baseline file cache

ComputerNative Intune settingMSI_MaxPatchCacheSize

Supported on Windows Installer v3.0

25H2 · 1.0

What it does

This policy controls the percentage of disk space available to the Windows Installer baseline file cache. The Windows Installer uses the baseline file cache to save baseline files modified by binary delta difference updates. The cache is used to retrieve the baseline file for future updates. The cache eliminates user prompts for source media when new updates are applied. If you enable this policy setting you can modify the maximum size of the Windows Installer baseline file cache. If you set the baseline cache size to 0, the Windows Installer will stop populating the baseline cache for new updates. The existing cached files will remain on disk and will be deleted when the product is removed. If you set the baseline cache to 100, the Windows Installer will use available free space for the baseline file cache. If you disable or do not configure this policy setting, the Windows Installer will uses a default value of 10 percent for the baseline file cache maximum size.

What it writes

Hive: HKEY_LOCAL_MACHINE
Registry key: Software\Policies\Microsoft\Windows\Installer

In Intune

Native Intune setting: Yes — Policy CSP

./Device/Vendor/MSFT/Policy/Config/ADMX_MSI/MSI_MaxPatchCacheSizeADMX_MSI on Microsoft LearnADMX-backed: Windows ships this template, so it is set with the template's own values, without an import.Windows builds listed: 10.0.22000, 10.0.19043.1202, 10.0.19042.1202, 10.0.19041.1202.

From Microsoft's Policy CSP DDF files (DDF v2 Files, February 2026), read 18 Oct 2026.

Options

Option	Type	Registry value	Allowed values
Baseline file cache maximum sizeDefault: 10	Number	`MaxPatchCacheSize`	0 to 100

Configure and deploy

Choose a state and the option values; the output below is generated from the template for exactly that.

Enabled · Computer · template defaults

Registry file (.reg)

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer]
"MaxPatchCacheSize"=dword:0000000A

PowerShell

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Control maximum size of baseline file cache
# Name: MSI_MaxPatchCacheSize
# Scope: Machine
# State: Enabled
# Source: MSI.admx

Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer' -Name 'MaxPatchCacheSize' -PropertyType 'DWord' -Value 10

These deployment candidates come from the ADMX template; they are separate from the native CSP mapping above.

The OMA-URI is an inferred ADMX-backed Policy CSP candidate derived from the source ADMX file name and policy name.
Some Microsoft policies use built-in Policy CSP pages whose area names don't match the ADMX file name, so verify the candidate against Microsoft Learn before deployment.

ADMX profile candidate (OMA-URI)

./Device/Vendor/MSFT/Policy/Config/ADMX_MSI/MSI_MaxPatchCacheSize

ADMX SyncML candidate

<SyncML xmlns="SYNCML:SYNCML1.2">
  <SyncBody>
    <Replace>
      <CmdID>1</CmdID>
      <Item>
        <Meta>
          <Format>chr</Format>
          <Type>text/plain</Type>
        </Meta>
        <Target>
          <LocURI>./Device/Vendor/MSFT/Policy/Config/ADMX_MSI/MSI_MaxPatchCacheSize</LocURI>
        </Target>
        <Data>&lt;enabled/&gt;
&lt;data id="MSI_MaxPatchCacheSize" value="10"/&gt;</Data>
      </Item>
    </Replace>
    <Final/>
  </SyncBody>
</SyncML>

Intune remediation scripts

Detection

$ErrorActionPreference = 'Stop'
$reasons = [System.Collections.Generic.List[string]]::new()

function Test-RegistryValueExists {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    return $null -ne (Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue)
}

function Test-RegistryValueEquals {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $Kind,
        [Parameter(Mandatory = $true)][object] $Expected
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    $valueObject = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue
    if ($null -eq $valueObject) {
        return $false
    }

    $actual = $valueObject.$Name
    switch ($Kind) {
        'String' { return [string]$actual -ceq [string]$Expected }
        'ExpandString' { return [string]$actual -ceq [string]$Expected }
        'DWord' { return [uint32]$actual -eq [uint32]$Expected }
        'QWord' { return [uint64]$actual -eq [uint64]$Expected }
        'MultiString' {
            $actualArray = @($actual)
            $expectedArray = @($Expected)
            if ($actualArray.Count -ne $expectedArray.Count) { return $false }
            for ($index = 0; $index -lt $actualArray.Count; $index++) {
                if ([string]$actualArray[$index] -cne [string]$expectedArray[$index]) { return $false }
            }
            return $true
        }
        'Binary' {
            $actualArray = [byte[]]$actual
            $expectedArray = [byte[]]$Expected
            if ($actualArray.Length -ne $expectedArray.Length) { return $false }
            for ($index = 0; $index -lt $actualArray.Length; $index++) {
                if ($actualArray[$index] -ne $expectedArray[$index]) { return $false }
            }
            return $true
        }
        default { return [string]$actual -ceq [string]$Expected }
    }
}

# Policy: Control maximum size of baseline file cache
# Name: MSI_MaxPatchCacheSize
# Scope: Machine
# State: Enabled
# Source: MSI.admx

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer' -Name 'MaxPatchCacheSize' -Kind 'DWord' -Expected 10
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer\MaxPatchCacheSize') | Out-Null
}

if ($reasons.Count -eq 0) {
    Write-Output 'Compliant'
    exit 0
}

$reasons | ForEach-Object { Write-Output $_ }
exit 1

Remediation

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Control maximum size of baseline file cache
# Name: MSI_MaxPatchCacheSize
# Scope: Machine
# State: Enabled
# Source: MSI.admx

Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer' -Name 'MaxPatchCacheSize' -PropertyType 'DWord' -Value 10

History 5 retained releases

22H2 · 1.015 Jul 2024
- Already present in the first release ChangeIntel keeps.

4 later releases left it unchanged.

Template

Internal name: MSI_MaxPatchCacheSize
Namespace: Microsoft.Policies.MSI
Template file: MSI.admx
Release: Windows 11 25H2 · 1.0 · file set de4e49983ebd651f…

Definition, editor controls and support

Definition

<policy class="Machine" displayName="$(string.MSI_MaxPatchCacheSize)" explainText="$(string.MSI_MaxPatchCacheSizeHelp)" key="Software\Policies\Microsoft\Windows\Installer" name="MSI_MaxPatchCacheSize" presentation="$(presentation.MSI_MaxPatchCacheSize)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.MSI:MSI" />
      <supportedOn ref="Microsoft.Policies.MSI:SUPPORTED_MSI30" />
      <elements>
        <decimal id="MSI_MaxPatchCacheSize" maxValue="100" valueName="MaxPatchCacheSize" />
      </elements>
    </policy>

Editor controls

<presentation id="MSI_MaxPatchCacheSize" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
        <decimalTextBox defaultValue="10" refId="MSI_MaxPatchCacheSize">Baseline file cache maximum size</decimalTextBox>
      </presentation>

Supported platforms and category

Microsoft.Policies.MSI:category:MSI
<category displayName="$(string.MSI)" name="MSI" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.Windows:WindowsComponents" />
    </category>
Microsoft.Policies.MSI:definition:SUPPORTED_MSI30
<definition displayName="$(string.SUPPORTED_MSI30)" name="SUPPORTED_MSI30" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
        <or>
          <reference ref="Microsoft.Policies.Products:WindowsInstaller30" />
        </or>
      </definition>
Microsoft.Policies.MSI:unresolved:Microsoft.Policies.Products:WindowsInstaller30
<unresolved reference="Microsoft.Policies.Products:WindowsInstaller30" />
Microsoft.Policies.Windows:category:WindowsComponents
<category displayName="$(string.WindowsComponents)" explainText="$(string.WindowsComponents_Help)" name="WindowsComponents" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Microsoft.Policies.MSI:category:MSI
<category displayName="$(string.MSI)" name="MSI" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.Windows:WindowsComponents" />
    </category>
<strings><string id="Microsoft.Policies.MSI:MSI">Windows Installer</string></strings>
Microsoft.Policies.MSI:definition:SUPPORTED_MSI30
<definition displayName="$(string.SUPPORTED_MSI30)" name="SUPPORTED_MSI30" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
        <or>
          <reference ref="Microsoft.Policies.Products:WindowsInstaller30" />
        </or>
      </definition>
<strings><string id="Microsoft.Policies.MSI:SUPPORTED_MSI30">Windows Installer v3.0</string></strings>
Microsoft.Policies.Windows:category:WindowsComponents
<category displayName="$(string.WindowsComponents)" explainText="$(string.WindowsComponents_Help)" name="WindowsComponents" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Microsoft.Policies.Windows:WindowsComponents">Windows Components</string><string id="Microsoft.Policies.Windows:WindowsComponents_Help">Contains settings for operating system components.</string></strings>