Define file shares for downloading security intelligence updates
Verified with Windows 11 25H2 — updated on July 30, 2026
Supported on: At least Windows Server 2012, Windows 8 or Windows RT
Path in the GPO console
Computer Configuration\Administrative Templates\Windows Components\Microsoft Defender Antivirus\Security Intelligence Updates Description
This policy setting allows you to configure UNC file share sources for downloading security intelligence updates. Sources will be contacted in the order specified. The value of this setting should be entered as a pipe-separated string enumerating the security intelligence update sources. For example: "{\\unc1 | \\unc2 }". The list is empty by default. If you enable this setting, the specified sources will be contacted for security intelligence updates. Once security intelligence updates have been successfully downloaded from one specified source, the remaining sources in the list will not be contacted. If you disable or do not configure this setting, the list will remain empty by default and no sources will be contacted.
Registry
HKLM
Software\Policies\Microsoft\Windows Defender\Signature Updates MDM / Intune (CSP)
./Device/Vendor/MSFT/Policy/Config/ADMX_MicrosoftDefenderAntivirus/SignatureUpdate_DefinitionUpdateFileSharesSources Multiple CSP matches are possible; the first one was selected.
Microsoft Learn documentation Mapping data: Microsoft Learn (CC BY 4.0)
Export Builder
BETAConfigure the state, scope and options, then generate .reg, PowerShell, Intune and SCCM outputs — or add the setting to a multi-setting collection.
These exports write the registry — this is not a managed GPO. ⓘ
.reg file
Windows Registry Editor Version 5.00
; Exported from gporais.com
; Policy: Define file shares for downloading security intelligence updates
; State: Enabled
; Supported on: At least Windows Server 2012, Windows 8 or Windows RT
[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows Defender\Signature Updates]
"DefinitionUpdateFileSharesSources"=""More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Define file shares for downloading security intelligence updates
# State: Enabled
# Supported on: At least Windows Server 2012, Windows 8 or Windows RT
$path = 'HKLM:\Software\Policies\Microsoft\Windows Defender\Signature Updates'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'DefinitionUpdateFileSharesSources' -Value '' -Type StringIntune XML
OMA-URI: ./Device/Vendor/MSFT/Policy/Config/ADMX_MicrosoftDefenderAntivirus/SignatureUpdate_DefinitionUpdateFileSharesSources
Data type: String
Value:
<enabled/>
<data id="SignatureUpdate_DefinitionUpdateFileSharesSources" value=""/>Intune Remediation
# === Detection script ===
# Exported from gporais.com
# Policy: Define file shares for downloading security intelligence updates
# State: Enabled
# Supported on: At least Windows Server 2012, Windows 8 or Windows RT
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Microsoft\Windows Defender\Signature Updates' -Name 'DefinitionUpdateFileSharesSources' -Expected '' -Kind String)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Define file shares for downloading security intelligence updates
# State: Enabled
# Supported on: At least Windows Server 2012, Windows 8 or Windows RT
$path = 'HKLM:\Software\Policies\Microsoft\Windows Defender\Signature Updates'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'DefinitionUpdateFileSharesSources' -Value '' -Type StringSCCM scripts
# Exported from gporais.com
# Policy: Define file shares for downloading security intelligence updates
# State: Enabled
# Supported on: At least Windows Server 2012, Windows 8 or Windows RT
# SCCM Configuration Item guidance:
# Create a Configuration Item of type "Setting: Script".
# Discovery script: use the Detection script below.
# Remediation script: use the Remediation script below.
# Compliance rule: the Discovery script output equals 'Compliant'.
# === Detection script ===
# Exported from gporais.com
# Policy: Define file shares for downloading security intelligence updates
# State: Enabled
# Supported on: At least Windows Server 2012, Windows 8 or Windows RT
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Microsoft\Windows Defender\Signature Updates' -Name 'DefinitionUpdateFileSharesSources' -Expected '' -Kind String)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Define file shares for downloading security intelligence updates
# State: Enabled
# Supported on: At least Windows Server 2012, Windows 8 or Windows RT
$path = 'HKLM:\Software\Policies\Microsoft\Windows Defender\Signature Updates'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'DefinitionUpdateFileSharesSources' -Value '' -Type StringBuilding a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.