Horizon offline mode.
Nickname, LAN, singleplayer.
Offline mode is the launcher's local start: a nickname instead of a Microsoft session, the same prepared game files, and the same profile folder. It is built for singleplayer, LAN worlds and servers that run in offline mode.
Official Horizon client: github.com/horizon-rust/horizon/releases. The xHorizon launcher downloads it for you.
A local start, step by step
Choose the nickname
3 to 16 letters, digits or underscores. The launcher passes it as --name and writes no session file. The same name is used in singleplayer and on every offline server you join.
Pick the profile
The selected pack keeps its own mods, options and worlds. Switching between online and offline does not move or copy the profile folder.
Join what accepts it
Singleplayer always works. A LAN world opened from an offline launch accepts the nickname. Public servers need offline mode on their side as well.
Where the mode stops
Licensed servers
An online-mode server verifies the join against a Microsoft session. The nickname has no session behind it, so the server closes the connection.
Skins and capes
The client has no account profile to fetch. Everyone sees the default skin until you switch back to a signed-in launch.
Account worlds
Worlds stored in the profile are local and stay. Anything tied to an account service rather than the folder is not part of offline mode.
Updates
The version is whatever is installed. Offline mode does not download a newer game or bypass the official updater.
Questions this page gets
What nickname can I use?
3 to 16 characters: Latin letters, digits and underscores. The launcher strips everything else and refuses a shorter or longer name before it starts the game.
Can friends join my LAN world?
Yes. A signed-in client can join a LAN world that accepts the nickname; the LAN host keeps the same world and settings. A public server is the case that fails.
Does offline mode use a fake account?
No. The game gets a name and no session. There is no token, no UUID from Microsoft and no account record. The server decides whether that is enough.
Can I switch back without losing the world?
Yes. The profile folder is the same. Turn offline mode off, sign in, and the next launch opens the same saves with the account name.
Which packs work offline?
Every installed pack. A pack with native mods starts its built client; a pack that was never built needs the normal install and native build first.
Same world, different login.
Offline mode is one switch in Settings. It starts the profile you already have; it does not create a second installation.
Offline mode starts prepared game files without a Microsoft session. It is not a license bypass and does not include Minecraft. Terms.