Download Failed Error Block for React

From two typed numbers: the file's size (2,400 MB) and the space the disk has (1,100 MB). The shortfall, the word beside it, the percentage the first attempt reached and the bar's stopping point are all worked out from those numbers by small pure helpers, so changing either one changes the page. A real page would read the free space from the operating system, which a browser can't do, or from your desktop app.

It adds what you say you could delete (nothing, 0.9 GB of old downloads, 1.6 GB of trash) to the free space and recomputes everything: with old downloads gone it is still short by 0.4 GB, with the trash emptied it has 0.3 GB to spare and the retry can finish. Nothing is deleted; the choice only moves the numbers.

Nothing is requested and nothing is saved. A press runs a bar from empty to its stopping point in under two seconds (at once when you prefer reduced motion) and then says what happened in a polite status line, ending "Simulated; nothing was saved." The button stays pressable while it runs but ignores the press, so nobody is stranded by a disabled control. In your app, start the download from the retry handler and move the bar from real progress events.

They are three native radio buttons in labelled cells, so the arrow keys, the label click and a screen reader all work with no script. The latencies are typed samples and the nearest one is the lowest of them. The connection cell repeats the chosen mirror's latency, and the button's label follows the choice.

They are the three things a download usually dies of, and a page that names them turns a vague failure into a short checklist. Connection and permission are typed as fine here, so the one thing to fix is the space; a real page would test each one and show the same cells.

The three requirements stack as short rows, the three mirrors stay side by side, and the bar and the retry button are pinned to the foot of the screen until you reach them, with Start over as an icon beside it.