Allow Internet Explorer to play media files that use alternative codecs: registry value EnableAlternativeCodecComputerHKLM\Software\Policies\Microsoft\Internet Explorer\Main

Policy ID: EnableAlternativeCodec
Scope: Computer Configuration, User Configuration
Supported on: At least Internet Explorer 9.0
Source: Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category: Windows Components › Internet Explorer › Internet Settings › Advanced settings › Multimedia

Registry

EnableAlternativeCodec

REG_SZComputerUser

…\Software\Policies\Microsoft\Internet Explorer\MainHKLM\Software\Policies\Microsoft\Internet Explorer\Main Current key
HKCU\Software\Policies\Microsoft\Internet Explorer\Main

Enabled value: yes
Disabled value: no

Apply with .reg · CMD · PowerShell

ComputerMachine-wide setting

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main]

; Options (use only one)
; Enabled
"EnableAlternativeCodec"="yes"
; Disabled
"EnableAlternativeCodec"="no"

CMD

:: Options (use only one)

:: Enabled
reg add "HKLM\Software\Policies\Microsoft\Internet Explorer\Main" /v "EnableAlternativeCodec" /t REG_SZ /d "yes" /f
:: Disabled
reg add "HKLM\Software\Policies\Microsoft\Internet Explorer\Main" /v "EnableAlternativeCodec" /t REG_SZ /d "no" /f

PowerShell

# Common: create the key
New-Item -Path 'HKLM:\Software\Policies\Microsoft\Internet Explorer\Main' -Force | Out-Null

# Options (use only one)
# Enabled
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Internet Explorer\Main' -Name 'EnableAlternativeCodec' -PropertyType String -Value 'yes' -Force | Out-Null
# Disabled
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Internet Explorer\Main' -Name 'EnableAlternativeCodec' -PropertyType String -Value 'no' -Force | Out-Null

UserPer-account setting

.reg

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main]

; Options (use only one)
; Enabled
"EnableAlternativeCodec"="yes"
; Disabled
"EnableAlternativeCodec"="no"

CMD

:: Options (use only one)

:: Enabled
reg add "HKCU\Software\Policies\Microsoft\Internet Explorer\Main" /v "EnableAlternativeCodec" /t REG_SZ /d "yes" /f
:: Disabled
reg add "HKCU\Software\Policies\Microsoft\Internet Explorer\Main" /v "EnableAlternativeCodec" /t REG_SZ /d "no" /f

PowerShell

# Common: create the key
New-Item -Path 'HKCU:\Software\Policies\Microsoft\Internet Explorer\Main' -Force | Out-Null

# Options (use only one)
# Enabled
New-ItemProperty -Path 'HKCU:\Software\Policies\Microsoft\Internet Explorer\Main' -Name 'EnableAlternativeCodec' -PropertyType String -Value 'yes' -Force | Out-Null
# Disabled
New-ItemProperty -Path 'HKCU:\Software\Policies\Microsoft\Internet Explorer\Main' -Name 'EnableAlternativeCodec' -PropertyType String -Value 'no' -Force | Out-Null