How to See, Add and Remove Codecs in Windows 11 and 10 (and Windows 95/98/Me)

Windows keeps its codecs in two different places, and neither shows up in Add or Remove Programs. Here is how to see what is installed, add what is missing and take out what is causing trouble on Windows 11 and 10 - with the Windows 95, 98 and Me method at the end.

A codec on Windows is either a Media Foundation component - built into Windows or installed as a Store extension - or a DirectShow filter registered by a codec pack or a single installer.

The two kinds are listed, added and removed in different ways, which is why a codec you know you installed can be nowhere in the Installed apps list.

Everything below is free, and the only downloads are two small tools.

See which codecs are installed

Start with the Store extensions, because they are the easy ones. Open Settings, Apps, Installed apps and type "extension" in the search box - HEVC Video Extensions, AV1 Video Extension, VP9 Video Extensions, MPEG-2 Video Extension and Web Media Extensions all appear here if they are installed.

The built-in Windows decoders and any DirectShow filters do not appear in that list. For those, InstalledCodec is a small portable tool that lists every ACM, VCM and DirectShow codec on the PC in one window, with its file, version and whether it is enabled.

If you already have the K-Lite Codec Pack, its Codec Tweak Tool does the same job from its codec and filter management screen, and also flags entries whose files have gone missing.

Add a codec

There are three ways in, and which one you want depends on which player needs the codec.

• Store extension. The only route that helps the Windows 11 Media Player app, Movies & TV and Photos - the Media Foundation Codecs bundle installs every Microsoft extension at once, HEVC included, for free.
• Codec pack. The route for Windows Media Player Legacy, MPC-HC, PotPlayer and every other DirectShow player - the K-Lite Codec Pack registers LAV Filters for HEVC, AV1, DTS, TrueHD, Xvid and the rest in one install.
• Single filter file. For one specific .ax or .dll decoder, register it with regsvr32 - the steps are in How to install and uninstall DLL and AX codec files.

Whichever route you use, install one codec pack at most. Two packs registering the same formats is the commonest cause of a player that worked yesterday and does not today.

Remove a codec

Removal follows the same split. Store extensions come out through Settings; DirectShow filters come out through the installer that put them in, or through a tool that edits the registrations.

• For a Store extension, open Settings, Apps, Installed apps, open its menu and choose Uninstall - if the button is greyed out, as it is on the HEVC extension from device manufacturers, open Terminal (Admin) and run the command below.
• For a codec pack, uninstall it from Installed apps, restart, then run the Codec Tweak Tool and let its Fixes scan remove any registrations the uninstaller left behind.
• For a single .ax or .dll filter, unregister it with regsvr32 /u followed by the file path, as an administrator, then delete the file.

Get-AppxPackage -AllUsers *HEVCVideoExtension* | Remove-AppxPackage -AllUsers

Disable instead of remove

Most codec conflicts are not solved by deleting anything. They are solved by stopping one decoder from answering first, and both tools above have a switch for exactly that.

In InstalledCodec, select the codec and use the Disable or Enable command on its menu. In the Codec Tweak Tool, the codec and filter management screen has a checkbox beside every entry, and the DirectShow preferred decoder settings let you choose which filter handles each format without touching any other.

Disabling is reversible in one click, which is why it is the right first move when you are not sure which codec is the problem.

Windows 95, 98 and Me: the original method

This page was first written in 2004 for the Windows 9x family, where codecs and MCI drivers were managed from one Control Panel screen. The steps still work on those systems.

• Open Control Panel, then Multimedia on Windows 95 and 98, or Sounds and Multimedia on Windows Me, and switch to the Devices tab - called Advanced on the original Windows 95.
• Expand Audio Compression Codecs or Video Compression Codecs to see what is installed; Media Control Devices holds the MCI drivers.
• To remove a codec, select it, click Properties and then Remove, and restart.
• To add one back, open Add New Hardware from Control Panel, choose to select the hardware from a list, pick Sound, video and game controllers, choose (Standard system devices) and click Have Disk.
• Browse to the Windows folder on the installation CD, open mmdriver.inf, pick the codec or MCI driver from the list and click Next, then restart.

Codec packs for these systems have not been maintained for many years, so the CD is the only reliable source for the default codecs.

Quick questions

Two lists, two tools, and you are in charge of every codec on the PC.

Download the K-Lite Codec Pack to add the missing decoders and get the Codec Tweak Tool in the same install, or tell us which codec you had to hunt down if you have been through this.