Block loading of COM/VSTO add-ins registered in HKCU
Verified with Microsoft 365/Office 5568.1000 — updated on July 10, 2026
Supported on: At least Windows Server 2016, Windows 10
Path in the GPO console
User Configuration\Administrative Templates\Microsoft Office 2016\Security Settings Description
This policy setting controls whether COM/VSTO add-ins registered only in HKEY_CURRENT_USER (HKCU) are blocked from loading. Standard users can install add-ins through ClickOnce deployment or the Office Add-ins settings, which typically register add-ins in HKCU rather than HKEY_LOCAL_MACHINE (HKLM). If you enable this policy setting, all COM/VSTO add-ins registered only in HKCU will be blocked from loading, preventing users from running add-ins they have installed without administrator privileges. If you disable or don't configure this policy setting, COM/VSTO add-ins registered in HKCU are allowed to load normally. Note: Add-ins registered in HKLM (typically installed by administrators) are not affected by this policy setting.
Registry
HKCU
software\policies\microsoft\office\16.0\common\security Value name: restrictcucomaddin
Enabled: restrictcucomaddin = 1
Disabled: restrictcucomaddin = 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: Block loading of COM/VSTO add-ins registered in HKCU
; State: Enabled
; Supported on: At least Windows Server 2016, Windows 10
[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\security]
"restrictcucomaddin"=dword:00000001More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Block loading of COM/VSTO add-ins registered in HKCU
# State: Enabled
# Supported on: At least Windows Server 2016, Windows 10
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
$path = 'HKCU:\software\policies\microsoft\office\16.0\common\security'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'restrictcucomaddin' -Value 1 -Type DWordIntune XML
No direct Policy CSP / OMA-URI mapping for this policy. Use the Intune Remediation tab, or ingest the ADMX in Intune.Intune Remediation
# === Detection script ===
# Exported from gporais.com
# Policy: Block loading of COM/VSTO add-ins registered in HKCU
# State: Enabled
# Supported on: At least Windows Server 2016, Windows 10
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
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
}
$checks = @(
(Test-RegistryValue -Path 'HKCU:\software\policies\microsoft\office\16.0\common\security' -Name 'restrictcucomaddin' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Block loading of COM/VSTO add-ins registered in HKCU
# State: Enabled
# Supported on: At least Windows Server 2016, Windows 10
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
$path = 'HKCU:\software\policies\microsoft\office\16.0\common\security'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'restrictcucomaddin' -Value 1 -Type DWordSCCM scripts
# Exported from gporais.com
# Policy: Block loading of COM/VSTO add-ins registered in HKCU
# State: Enabled
# Supported on: At least Windows Server 2016, Windows 10
# 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: Block loading of COM/VSTO add-ins registered in HKCU
# State: Enabled
# Supported on: At least Windows Server 2016, Windows 10
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
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
}
$checks = @(
(Test-RegistryValue -Path 'HKCU:\software\policies\microsoft\office\16.0\common\security' -Name 'restrictcucomaddin' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Block loading of COM/VSTO add-ins registered in HKCU
# State: Enabled
# Supported on: At least Windows Server 2016, Windows 10
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
$path = 'HKCU:\software\policies\microsoft\office\16.0\common\security'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'restrictcucomaddin' -Value 1 -Type DWordBuilding a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.