Open the file using a versatile media player like VLC Media Player , which handles .mkv files and various codecs natively.
Do you have on where this file was found or what you expect the video to be? AgADkwgAAmRUiFY.mkv
If you did not personally trigger this download or receive it from a trusted contact, exercise caution. MKV files themselves are generally safe, but they are often used to distribute large media files from unknown sources. Open the file using a versatile media player