Why an upload failed, and which errors are worth retrying

The connection dropped

Symptom: the transfer stops partway with a network error. A resumable upload session can be continued rather than restarted, so a good tool resumes from where it stopped instead of sending the whole file again. If you are uploading by hand in a browser, retrying from the same page will usually resume.

Quota exceeded

The YouTube Data API gives each application a daily allowance, and uploads have their own separate one: a hundred uploads a day, plus ten thousand units a day for everything else a tool does. If you see a quota error, nothing is wrong with your video or your account, and retrying will fail identically until the allowance resets at midnight Pacific time.

There is also an undocumented limit on uploads per day that Google does not publish and does not show in its own console. It arrives as a 429 rather than the usual 403, and people have run into it well below a hundred. There is nothing to do about that one except wait for the reset.

This is also the reason a third-party tool can have a bad day that is nothing to do with you: the allowance is per application, shared across all of its users. Any tool that lets you supply your own Google client, as Runsheet does under Advanced on the connect page, moves you onto an allowance nobody else is spending.

Thumbnail rejected

Custom thumbnails require a verified YouTube account. If yours is not verified the upload succeeds and the thumbnail is refused, which is confusing because it looks like a partial failure. Verify the account in YouTube settings, then set the thumbnail again. The other common cause is the file itself. YouTube wants a JPG or PNG, and its thumbnail help caps the size at 2MB from a phone and 50MB from a computer; Runsheet’s own thumbnail upload holds to 2MB. There is also a daily limit on how many custom thumbnails a channel can upload, and hitting it means waiting a day rather than fixing anything.

Playlist write forbidden

A 403 on a playlist write usually means the access token was granted before the playlist permission was requested, so the token does not carry the scope. Reconnecting the account and accepting the full permission set fixes it. Nothing about the video is wrong.

Processing abandoned

YouTube accepted the file and then gave up processing it. This is almost always a codec or container problem rather than a size problem. Re-exporting to H.264 in an MP4 container fixes the large majority of cases. Very long videos in exotic formats are the usual offenders.

What a tool should do about it

An upload cannot be undone, so everything after it has to be treated as best effort. If a thumbnail or a playlist write fails, the right behaviour is to keep the video, tell you precisely what failed, and offer a retry of just that step. Rolling back a published video is not available, and a tool that hides a partial failure behind a generic error message has cost you the one thing you needed: knowing which step to redo.