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FAQ

Peers do not appear​

  • Same passphrase on every machine (exact match, case-sensitive).
  • Same LAN: Mercury does not sync over the public internet.
  • Firewall allows TCP 47821.
  • mDNS enabled on your router (default on most home networks).

Mercury retries discovery automatically when the network changes or no peers are found for a while, so you should not need to restart sync.

Dual-boot: why is one machine shown twice?​

If you dual-boot a single machine (e.g. Windows and Linux on the same hardware), each OS used to announce itself under a different hostname with the same IP, so Mercury showed the same physical machine twice.

Mercury now identifies peers by a stable machine ID — a random value generated once and advertised in the mDNS TXT record. The same physical machine therefore appears once, regardless of which OS is booted. The name shown is whichever OS last announced its hostname.

Passphrase mismatch​

If peers appear but clipboard never syncs, passphrases may differ. After several decrypt failures, Home shows a warning. Set the same secret on all devices and restart sync.

VPN​

Mercury may show a VPN detected warning when a named VPN client interface is active (WireGuard, Tailscale, etc.). macOS system utun tunnels are ignored.

VPNs can block or skew LAN discovery. If sync fails, disable the VPN temporarily and retry on the same network.

Linux tray missing (GNOME / Pop!_OS)​

Install AppIndicator support. The .deb lists libayatana-appindicator3-1 as a dependency. If the icon is still missing, install the GNOME extension and log out/in.

Clipboard not syncing despite peers​

  • Confirm sync is not paused in Settings.
  • Mercury only watches the clipboard when peers are connected.
  • Payloads over 25 MB are ignored for clipboard sync. Use file transfer instead.

Is the logo medical?​

No. The caduceus (two snakes, wings) is the symbol of Mercury/Hermes. The medical Rod of Asclepius has one snake and no wings.

How is this different from a clipboard manager?​

Clipboard managers store history. Mercury forwards the current clipboard to peers and does not keep an archive.