Transfer manager

The transfer manager is a docked panel in the bottom-right of the app. It is mounted once for the whole authenticated app, so it survives navigation: start an upload, open another folder, preview a file: your transfers keep going and stay visible. When there's nothing in flight and nothing finished to review, the panel simply isn't there.

It also stays out of your way without hiding work: the dock stays visible while anything is active or has failed, and can't be swiped away while a transfer is in flight: only a fully-settled dock can be flicked aside, and it comes back the moment a new transfer starts. If you try to close the tab while transfers are actively moving, the browser warns you first, since closing would kill the chunks in flight.

Uploads and downloads share the panel. In-flight work sorts to the top and finished work sinks to the bottom, with a header summarizing how many transfers are active or failed and a Clear completed action to tidy up.

Each transfer shows its own live status, and what you can do depends on its direction and state:

• •Direction at a glance: an animated arrow marks every row: an upload arrow nudging up, a download arrow nudging down, so you can tell which way a transfer is going without reading the label.
• •Progress, speed & ETA: a per-item progress bar whose fill tracks the true byte ratio (so it never appears to stall), with an estimated time remaining. Uploads add a live transfer speed drawn from a smoothed byte rate.
• •Pause / Resume: for uploads and downloads: hold a transfer without losing what's already done, then continue where it left off.
• •Retry, re-run a failed transfer. A single file continues from what's already done rather than starting over; a multi-file ZIP restarts.
• •Stop / Cancel: end a download (Stop) or an upload (Cancel) that's in progress. This is the destructive action, distinct from Pause.
• •Dismiss: clear a finished or interrupted row from the list. For an unfinished upload this is non-destructive (below).

Pausing an upload stops it at a chunk boundary: it finishes the chunk in flight and then holds, so the server-side upload session and the per-file key are preserved. Resuming continues from the chunks already uploaded rather than starting over, re-using that same session and key. Downloads pause the same way: a paused download keeps everything decrypted so far (and, for a large download streaming to disk, the open file), and resumes from there. Pausing is deliberately distinct from Stop / Cancel, a pause preserves state, a stop discards it.

The two directions differ in how long a hold survives. An interrupted upload's progress is tracked on the server, so you can pick it back up even after a reload or closing the tab. A download's partial state lives only on your device, so closing the tab restarts it. See Downloading.

There are two ways to clear a row, and they mean different things. Dismiss: the ✕ on a finished row, or a sideways swipe on a settled dock, just removes the row from the panel. For an upload that hasn't finished, dismiss is non-destructive: it hides the row but leaves the upload's server-side session intact, so a stray swipe can never delete a partial upload. Downloads have no server-side state, so dismissing one just removes its row. Cancel (uploads) and Stop (downloads) are the destructive actions that actually end a transfer.

When you want it out of the way, collapse the panel down to a compact pill that shows a single aggregate progress bar across all running transfers. Expand it again any time to see the full per-item list.

• •Uploading: how the resumable upload sessions work underneath
• •Downloading: streaming, worker-pool decryption, and resume
• •Sync & device transfer: the peer-to-peer tool, not this panel
• •The transfer manager, the feature tour