Magnet links and .torrent files

A magnet link starts a download from a web page. It isn’t a file: it’s a short address, beginning magnet:, that names the download by a fingerprint of its contents. Your torrent app uses it to find people who have the download, and gets its list of files from them.

A magnet link looks like this, usually much longer:

magnet:?xt=urn:btih:0123456789abcdef0123456789abcdef01234567&dn=Big+Buck+Bunny&tr=udp%3A%2F%2Ftracker.example.org%3A1337

• xt is the fingerprint, called the info hash. It’s the only part a magnet link needs.
• dn is the download’s name, to show while its file list arrives.
• tr is a tracker, a server that introduces people sharing the download. There can be several, or none.

Open one

Click the link in your browser. If OrbTorrent is your Mac’s default torrent app, it opens in OrbTorrent, which asks which files you want and where to save them.

Your browser checks with you first:

• Safari asks whether to allow the page to open OrbTorrent, every time. Click Allow.
• Chrome asks whether to open OrbTorrent. Tick Always allow to stop it asking on that site, then click Open OrbTorrent.
• Firefox asks whether the site may open the link. Choose OrbTorrent, and tick that it should always do so.

You can also add a magnet link without clicking it:

• Copy it, then open OrbTorrent’s menu bar panel: it offers Add “…” from Clipboard.
• Paste it into the OrbTorrent window, with ⌘V.
• Choose File › Add Magnet Link… (⌘U), and paste it there.

A magnet link carries no file list, so OrbTorrent shows Fetching Info until someone sharing the download sends it, usually within seconds. Your first download explains the rest.

Choose the app that opens them

macOS has no setting of its own for magnet links: each torrent app has a switch to make itself the default, and whichever app last used it opens them.

To make it OrbTorrent, open Settings › General and click Make OrbTorrent the Default. From then on, magnet links in your browser and .torrent files in Finder open in OrbTorrent. OrbTorrent also offers this when you first open it.

If nothing happens

• No app is set to open them. Make OrbTorrent the default, as above, then click the link again.
• Another app opens them, often after you’ve installed or updated another torrent app. Make OrbTorrent the default again.
• Your browser remembers saying no. Firefox keeps your choice in Settings › General › Applications, next to magnet: set it to OrbTorrent, or Always ask.
• The link doesn’t start with magnet:?. You may have copied only part of it. Copy the whole link again.

Whatever the browser does, you can always copy the link and add it from OrbTorrent instead.

.torrent files

A .torrent file holds what a magnet link does, plus the download’s file list, so it can start straight away. Some sites offer one instead of, or as well as, a magnet link.

• Double-click it in Finder, and it opens in your default torrent app.
• To open it in OrbTorrent this once, Control-click it and choose Open With › OrbTorrent.
• To have every .torrent file open in OrbTorrent, select one, choose File › Get Info, choose OrbTorrent under Open with, and click Change All.

You can also drag a .torrent file onto OrbTorrent’s window, or choose File › Open Torrent File… (⌘O). Downloading .torrent files saves them to your Downloads folder, where you can delete them once the download has started.

Are they safe?

A magnet link or a .torrent file only describes a download. Opening one can’t run anything on your Mac.

What it downloads can still be a fake, such as a “film” that’s really a program. OrbTorrent’s Fake Download Check looks at a download’s files as soon as their list arrives, before any of them do, and holds one that looks fake until you decide. Checks and held downloads explains.