How to Open an MKV File (and Fix No Sound)

An .mkv file is a video container. Install the free VLC player and it plays, including files Windows Media Player refuses. There is nothing to buy and no codec pack to hunt down.

A .mkv file usually works fine, until it does not. Either the file refuses to open, or the video plays with no sound, and both problems trace back to one cause.

One free program fixes almost every .mkv problem

Most players fail on a .mkv file because they are missing a piece, not because the file itself is broken. VLC (free, from videolan.org) plays .mkv files, including ones using HEVC, with nothing extra to buy or install.

1. Download VLC free from videolan.org.
2. Install it like any other program.
3. Right click the .mkv file and open it with VLC, or double click it if VLC is already your default player.

That is why VLC is the simple answer for almost everyone.

On a Mac, the built in QuickTime Player will not open a .mkv file at all. VLC works the same way there as on Windows, and IINA is another free option if you would rather use that instead.

It is worth confirming you actually have a .mkv file and not something similarly named. Here’s how to show file extensions in Windows so you can check before you install anything.

Why one .mkv file plays and another does not

The short answer is that .mkv is not a video format the way JPG is a photo format. It is the Matroska container, and a container works more like a box than a flavor.

One .mkv file holds the video, the audio tracks, the subtitles and the chapters together in a single file. Whether a player can open that box depends on the codec packed inside, most often H.264 or HEVC (also called H.265).

This is why the built in Windows Media Player plays some .mkv files and chokes on others. It handles H.264 fine.

Many newer .mkv files use HEVC instead, and Windows does not include that codec by default. Microsoft sells the HEVC Video Extensions in the Microsoft Store for a small fee.

VLC skips this whole problem. It bundles its own codecs, HEVC included, so it opens the box regardless of what is packed inside.

When the video plays with no sound

A silent .mkv is almost never a broken file. The cause is usually an audio codec your player does not support, or the wrong audio track selected, and VLC can fix both.

Dual language files are a common trigger, since they carry more than one audio track in the same file.

1. Open the .mkv file in VLC.
2. Go to Audio, then Audio Track.
3. Choose a different track and check whether sound returns.

That single menu often solves it.

Turning subtitles on, off, or to another language

Subtitles are usually built into an .mkv file already, so there is rarely a separate subtitle file to hunt down.

1. Open the .mkv file in VLC.
2. Go to Subtitle, then Sub Track.
3. Pick a different language, or choose Disable to turn subtitles off.

Switching takes seconds once you know where to look.

Converting an .mkv file to MP4

Some phones, TVs and older devices will not play a .mkv file directly. Converting to MP4 first solves that.

1. Install HandBrake from handbrake.fr.
2. Open the .mkv file in HandBrake.
3. Choose one of the MP4 presets and start the conversion.

Converting re-encodes the video, so it takes time and always loses a little quality. There is no way around that trade off.

This does not mean the original was somehow better.

An .mkv file is not automatically better or worse quality than an .mp4. The quality comes from the video encoded inside, not from the container wrapped around it.

MKV is not the only video file that trips up a standard player this way. DVD-sourced .vob files cause similar confusion, and there is a separate guide on how to open a VOB file if you run into one of those too.

Frequently asked questions

What program opens an .mkv file?

VLC, free from videolan.org, opens almost every .mkv file, including ones using HEVC. On a Mac, IINA is another free option.

Why will Windows Media Player not play my .mkv file?

Many .mkv files use the HEVC codec, which Windows does not include by default. Microsoft sells the HEVC Video Extensions in the Microsoft Store, or you can skip that and use VLC instead.

Why does my .mkv file play with no sound?

Usually the player does not support the audio codec, or the wrong audio track is selected on a dual language file. Switching tracks under Audio, then Audio Track, in VLC usually fixes it.

How do I convert an .mkv file to MP4?

Use the free HandBrake (handbrake.fr) and choose one of its MP4 presets. The conversion re-encodes the video, so it takes time and always loses a little quality.

Is .mkv better quality than MP4?

Not automatically. Quality comes from the video encoded inside the file, not from the container format wrapping it.