When I click on an MP4 or MKV file in the Unraid file manager, it just pops up a message saying "Unsupported Preview".

I have watched a SpaceInvaderOne video of tweaking the extensions of file types you can open. There is no mention of MP4 or MKV in the editor.cfg file, but later in the video, he just clicks an MP4 file and it plays the video. How can I get this functionality to work?

Any help much appreciated.

Those extensions are for editing text files, I don't believe video playback is supported. You're going to want to use something like VLC to connect over the network to view video files through an SMB share or something.

You can edit the editor file on the boot usb and add the video extensions but be warned this likely won't work.

Edited January 28Jan 28 by MowMdown

Thank you. Yes I tried that, and as predicted, it didn't work.

On Spaceinvaderone's video on Youtube called "2 Minute Tips - Unraid File Manager Tweaks" and go to 3:10 you can see him open a JPG and play an MP4?

That might be browser dependent. Images are fine here on Chrome/win but not video.

I have tried it on Chrome and Edge and still "Unsupported Preview" Was it maybe a feature that a recent release has removed?

You did NOT add the image extensions to the editor.cfg file, right?

Yes. I tried that, and it would just open the file as text (eventually) so I removed all video extensions from editor.cfg.

On 1/28/2026 at 11:39 AM, ssmith369 said:

When I click on an MP4 or MKV file in the Unraid file manager, it just pops up a message saying "Unsupported Preview".

I have watched a SpaceInvaderOne video of tweaking the extensions of file types you can open. There is no mention of MP4 or MKV in the editor.cfg file, but later in the video, he just clicks an MP4 file and it plays the video. How can I get this functionality to work?

Any help much appreciated.

I'm also having trouble showing file previews in the Unraid file manager (as browsers I use Firefox, Chromium and sometimes Chrome).

As described here: https://forums.unraid.net/topic/120982-dynamix-file-manager/page/22/#findComment-1589494 I used to be able to even watch mp4 videos in the browser (not in the same tab) by opening the files via mouse-wheel-click to open them in another tab and then they would play in the browser. It would not work in the same tab as the file manager.

It also used to work for jpg files without problems.

After adding the file types to the editor.cfg I get code gibberish since it tries to open the jpg files as a text file.

Strange thing is: gif files will open as preview in the browser when clicking on them as animated gifs.