Your chapter list is in the description and nothing happened

Every chapter's length is the distance to the next one, and the last chapter has no next one — its length is whatever remains of the video. The ten-second minimum still applies to it, invisibly, because nothing in the description says where the video ends. An entry dropped near the outro for a final ID can be four seconds long while looking no different from the rest of the list.

It matters because of how the failure behaves. YouTube does not discard the offending entry and keep the others; the whole list stops being chapters, so one afterthought at the end switches off nineteen good ones. This is also the rule that cannot be checked from a project file: the check here compares each entry with the one before it, and a project file says nothing about the length of the finished render. If your last entry sits close to the end, measure that gap yourself.

A description is not validated, it is scanned. Lines that read as a time followed by a title are taken, everything else stays ordinary text, and nothing marks a line that was passed over. A discarded line still removes an entry from the count: lose the top line and the list no longer starts at 0:00, lose one line of four and two chapters are left, which fails a rule you were never close to failing.

The shape that reads dependably is the time first, then a space, then the title. Entries get lost when something sits in front of the time — a track number, a bullet, a dash, an opening bracket, an emoji — or when the title has been turned into a link. Those are the decorations a tracklist picks up on its way through a formatted document, a notes app or a forum post.

Two smaller things break lists that are otherwise clean. Times have to climb, so two entries on the same second, or one left out of sequence after a forgotten track went back in, breaks the list from that point down. Past the hour mark the times belong in H:MM:SS rather than a minute count still running past 59:59, which is outside the format YouTube documents.

Some of those shapes are options here, which makes them worth checking before anything gets rewritten. The numbered tracklist preset puts 1. in front of the time, which is the convention on a forum and the wrong thing in a description box. Title first moves the time into brackets at the end of the line, where YouTube does not look for it.

Precision is the one that catches people out. Set to tenths or milliseconds it writes 1:23.500, which is what a video editor wants and not what a description takes. Choosing the YouTube preset afterwards does not undo it: that preset sets the numbering, the order, the separator, the time style and the opening entry, and leaves precision on whatever was last chosen.

Chapters do not appear while a video is still processing, and a two-hour mix uploaded at high resolution keeps processing for a while after it goes public. Description edits are not instant either, and a few minutes is normal. Look at the watch page in a fresh tab rather than the Studio editor, which shows the text you typed rather than YouTube's reading of it.

After that, look at the video rather than the text. The automatic chapters checkbox in Studio governs the chapters YouTube generates for itself when you have written none, so turning it on rescues nothing that fails a rule. Audience and age settings are worth ruling out as well: videos marked made for kids lose a range of features, and chapters are among the things reported missing on them. None of this surfaces next to the description, which is how a sound list ends up rewritten five times.

The tracklist here is read out of whatever your software already wrote — an Ableton .als, an FL Studio .flp, a rekordbox .cue, a Traktor .nml, or a Serato session or its History CSV export — and then checked against YouTube's rules as you format it. The report names the failing rule and counts: how many entries there are when there are fewer than three, and how many gaps come in under ten seconds. Start at 0:00 adds an opening entry only when the first marker lands after the start, so it can be left switched on without ever displacing a real timestamp.

What it cannot do is see anything on YouTube's side: whether a video is still processing, how long the render is, what the audience setting says. A list that checks clean while the progress bar stays one unbroken line points at the video rather than the text. It cannot identify tracks from audio either — it reads project and session files, and there is no fingerprinting here. Everything runs in your own browser tab, so nothing is uploaded, there is no account, and there is no paid tier.