How do I play MKV on Mac? Sequoia

nickyyw wrote:

Is there a built-in trick I’m missing, or is a third-party player the only real option?

The free VLC will play them just fine. Along with others.

Third-party period for .mkv. I tend to play my .mkv videos with MacGo's Blu-ray Player Pro rather than VLC, which I also have installed. Simply a personal choice. I use the free, unregistered Blu-ray Player Pro.

The free Handbrake app can convert those .mkv into other formats including .mp4.

The MacGo Blu-ray Player Pro can also play DVDs and individual video files too. I watch my Blu-ray discs on my LG UBK-90 4K UltraHD Blu-ray player (upscales to 4K as needed) connected to the 55-in TV. The LG can also play MKV, WAV, etc. from a USB stick or a Linux EXT3 formatted hard drive.

Once I bought the LG UBK-90, I also purchased 1917, Midway, a few more in UltraHD 4K format — but not many. Handily, the LG will upscale 480p and higher video files to 4K (usually) without artifacts, so very handy for the Synology served video collection.

Most people think MKV itself is the problem, but it’s really not. The issue is what’s inside—MKV is just a container, like a box holding different types of video, audio, and subtitle tracks. macOS (and by extension, QuickTime) only supports a limited set of codecs, so if the video is encoded with something like certain versions of HEVC or the audio track is in DTS, QuickTime just throws its hands up.

There’s no built-in fix for this. QuickTime won’t magically start playing MKV files, and macOS Sequoia hasn’t changed anything in that regard. If you want to watch them without issues, the easiest way is to use a media player that supports MKV natively—no need to mess with conversions or codec workarounds.

That said, not all MKV files are created equal. Some play fine, others stutter or have missing audio, which usually comes down to high-bitrate files or unsupported audio formats. On newer Apple Silicon Macs, hardware acceleration can help with smooth playback, so if you’re getting lag, it’s worth checking if your player supports that.

If you’re looking to do more than just watch—like AirPlay streaming, editing, or using MKV files in Apple’s ecosystem—converting them to MP4 is really the only way to make them fully compatible. But if it’s just about playing the file, a proper media player is the easiest answer.

Curious—are you running into playback issues with a specific MKV file, or just looking for a long-term solution?

VikingOSX wrote:

The free Handbrake app can convert those .mkv into other formats including .mp4.

Before doing that I would just try some of the other recommended players such as VLC. I have only ever encountered one really strange format video I got off Facebook 8 years ago that VLC wasn't able to play.

MKV is a container and you may find your files contain audio and video components that might also be perfectly happy if they were in a container such as MP4 or MOV that Quicktime would play. If this is the case here, I would NOT use Handbrake to change the MKV to another format since Handbrake will re-code the video part at least with ensuing quality loss. One thing to try would be to use the free Subler to re-package the MKV file's components into a MP4 wrapper and see if it will do that (has to be acceptable codecs for the components) and if that plays. No quality loss and also a lot faster.

MKV playback on macOS has always been a bit of a gray area, and QuickTime hasn’t made any effort to change that. It’s not that macOS can’t handle high-quality video—it absolutely can—but QuickTime was never designed to support every format under the sun. That’s why trying to force MKV to work natively is a losing battle.

I use Elmedia Player for MKV files, it just works without extra tweaking. The thing with MKV is that it’s not a format in itself, but a container that can hold all sorts of different codecs for video, audio, and subtitles. Some MKVs are encoded in a way that macOS-friendly players can handle easily, while others include things like DTS audio, VobSub subtitles, or high-bitrate HEVC that require extra processing power.

If you're running into choppy playback or out-of-sync audio, it’s usually one of two things: either the file is too demanding for your hardware, or the media player isn’t making full use of hardware acceleration. Newer Apple Silicon Macs have amazing video decoding capabilities, but only if the player knows how to use them. This is why some MKV files play buttery smooth on one app and stutter like crazy on another.

There are a few other players worth mentioning—5KPlayer and Movist also handle MKV well and have decent performance on macOS. Some people prefer one over the other depending on their workflow, but in general, any player with proper codec support and GPU decoding will get the job done.

Now, if you’re trying to do more than just watch—like AirPlay streaming, embedding in projects, or editing—MKV will be a pain no matter what. That’s where converting to MP4 becomes a good option. It keeps the original quality (if done right) and makes the file usable across QuickTime, iMovie, and pretty much the entire Apple ecosystem. But if it’s just about watching movies or shows, there’s really no reason to go through the extra step of conversion when a good media player can handle it instantly.

IINA is actually set as the default on my iMac to play MKV files. I don't have MacGo's app installed since I've never owned a Blu-ray disc.

We bought a Sony Blu-ray player in 2014 which is connected to our TV. Still don't have any Blu-ray discs. :)

I think we bought six DVDs with the player. Not sure we watched all six. I have watched A Clockwork Orange a few times.

VLC can play most any video out there. IINA probably can too.