If you’ve ever tried to skip forward or backward in a video file, only to experience a frustrating 10-second freeze, or if you’ve attempted to stream an MKV file and found that the progress bar doesn’t work, you’ve encountered a problem with the MKV index.
| Error Message | Cause | Solution |
|----------------|---------|----------|
| "Invalid Cues" | Index references a byte offset outside file bounds | Remux with mkvmerge --cues 0 to rebuild cues from scratch |
| "No seek head found" | Index completely missing | mkvmerge without any --cues flag; it will create a default index |
| "Index is huge (over 10% of file)" | Too many cue points (e.g., every frame in 4-hour video) | Remux with --cues 5s to reduce density |
| "Seek works but audio goes out of sync" | Cues point to video clusters but not audio clusters | Remux and let mkvmerge recalculate all track positions |
What is an MKV Index?
. Modern consensus is that this is a waste of space and can actually confuse some media players. Loading Delays