"no such session" or a session won't attach

reach connect <session> replies no such session, reach sessions shows no hosts, or attaching sits there and never gives you a prompt.

What it means

Sessions are owner-only: you attach to sessions on your own machines, hosted by a client signed in to the same account. If the host isn't running, isn't signed in as you, or the name doesn't match what the host advertises, there's nothing to attach to.

Fixes, in order

  1. List first. Run reach sessions on the device you're attaching from. It shows your hosts and the session names each one offers; copy a name exactly from that list. If the list is empty, the problem is on the host side (next steps).
  2. Check the host is hosting. On the host: tray → Host sessions on this PC should be on, or reach host should be running in a terminal (headless). The host must be signed in to the same TYO ID.
  3. On a Mac, use the DMG build to host. The Mac App Store build can attach to sessions but can't host them — session hosting is unavailable in that build. Install the notarized DMG from the download page on the Mac that should host.
  4. On Windows, attach to a fresh session. Windows can't attach to a cmd or PowerShell window you already have open; reach host offers new sessions (PowerShell, CMD, Bash, WSL). For reattach-able sessions on Windows, run tmux inside WSL and reach host from WSL. See Reach Sessions.
  5. Name the host when names clash. reach connect <host> <session> picks the session on a specific machine if two hosts use the same session name.
  6. Check both ends can reach a gateway. Same-LAN attaches go peer-to-peer, otherwise via the gateway; if either side shows gateway unavailable, fix that first — connected but no internet.
  7. Update both ends. Sessions arrived in 1.9.53 and the reach alias in 1.9.54; an older host or client won't see the other. Check the tray version line.

Common questions

Can I share a session with a colleague?

No — sessions are deliberately owner-only. To give someone access to a machine, use Share this PC.

Does the proxy need to be on for sessions?

No. Hosting and attaching work independently of the Proxy: ON/OFF toggle.

The session attaches but shows a blank screen

Press Enter or resize the terminal; a tmux session redraws on the next input. If it stays blank, detach (Ctrl-]) and attach again.

Still stuck?

Get in touch with the output of reach sessions and the host's platform and version.