While a video uploads, its frame in the library reads "Transferring your recording" and its status reads "Uploading" with a percentage. The upload runs in the tab that started it, so the hint says: "Keep this page open until the upload finishes."
Why it stops
The tab was closed, the computer went to sleep, or the connection dropped. The part already uploaded is kept.
How Vistralo flags it
An upload with no progress for an hour is marked "Stalled", and the project is counted under "Needs attention". The project's page explains: "The upload stopped when its page was closed or the connection dropped."
Resuming it
- Open the project, or press "Resolve" on its frame.
- Press "Choose the file again" and select the same file from your computer.
- The upload carries on from where it stopped. Keep the tab open this time.
It has to be the same file.
If the upload is still running elsewhere
If the same project is uploading in another tab or window, leave it alone. Choosing the file again in a second tab is not needed.
If you no longer have the file
A recording made in the browser may still be in the recovery copy. Open a recording form and see whether it is offered. See A recording left unsaved. Otherwise use "Move to Trash" and start again.
Stuck on "Queued" or "Processing"
Those are jobs, and a job is handled differently from an upload. A queued job with no change for 30 minutes, or a running one with none for 90, is also marked "Stalled". Use "Cancel the job" to get the project back as a draft, and start it again later. Your recording is kept.