Lock Encrypted Media Extensions
Verified with Mozilla Firefox v8.2 — updated on July 10, 2026
Supported on: Firefox 77 or later, Firefox 68.9 ESR or later
Path in the GPO console
Computer Configuration\Administrative Templates\Mozilla\Firefox\Encrypted Media Extensions User Configuration\Administrative Templates\Mozilla\Firefox\Encrypted Media Extensions Description
If this policy is enabled and EncryptedMediaExtensions are disabled, Firefox will not download encrypted media extensions (like Widevine) or ask the user to install them. If this policy is disabled or not configured, it has no effect.
Registry
HKLM
Software\Policies\Mozilla\Firefox\EncryptedMediaExtensions HKCU
Software\Policies\Mozilla\Firefox\EncryptedMediaExtensions Value name: Locked
Enabled: Locked = 1
Disabled: Locked = 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. ⓘ
Applying both scopes creates an ambiguous configuration (computer takes precedence over user). Only do this intentionally.
.reg file
Windows Registry Editor Version 5.00
; Exported from gporais.com
; Policy: Lock Encrypted Media Extensions
; State: Enabled
; Scope: Computer (HKLM)
; Supported on: Firefox 77 or later, Firefox 68.9 ESR or later
[HKEY_LOCAL_MACHINE\Software\Policies\Mozilla\Firefox\EncryptedMediaExtensions]
"Locked"=dword:00000001More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Lock Encrypted Media Extensions
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 77 or later, Firefox 68.9 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\EncryptedMediaExtensions'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'Locked' -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: Lock Encrypted Media Extensions
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 77 or later, Firefox 68.9 ESR or later
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
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Mozilla\Firefox\EncryptedMediaExtensions' -Name 'Locked' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Lock Encrypted Media Extensions
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 77 or later, Firefox 68.9 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\EncryptedMediaExtensions'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'Locked' -Value 1 -Type DWordSCCM scripts
# Exported from gporais.com
# Policy: Lock Encrypted Media Extensions
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 77 or later, Firefox 68.9 ESR or later
# 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: Lock Encrypted Media Extensions
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 77 or later, Firefox 68.9 ESR or later
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
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Mozilla\Firefox\EncryptedMediaExtensions' -Name 'Locked' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Lock Encrypted Media Extensions
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 77 or later, Firefox 68.9 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\EncryptedMediaExtensions'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'Locked' -Value 1 -Type DWordBuilding a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.