For fans of the industrial revolution city-builder, "Anno 1800 LAN multiplayer fixed" has become a rallying cry for those trying to enjoy stable local or online sessions. While the game technically uses a lock-step mechanism to sync game states across all PCs—meaning only user inputs are shared to keep bandwidth low—this system often leads to frustrating "desync" events.
Whether you’re playing on a literal Local Area Network (LAN) or just trying to get a stable co-op session running through the internet, here is the comprehensive guide to fixing multiplayer issues in Anno 1800. 1. Fix Connection & Invitation Errors (LR05, LR39)
If you can’t even get your friends into the same lobby, the issue is usually related to how Ubisoft Connect communicates with your network or the game client.
Invite via Ubisoft Connect, not Steam: Many players find that the in-game "invite" button fails. Instead, minimize the game, open the Ubisoft Connect Desktop App, right-click your friend in the list, and select "Invite to Game" from there.
Disable IPv6: A common fix for "failed to connect to remote IP" (LR39) is to disable IPv6 on your network adapter. This forces the game to use the more stable IPv4 protocol.
Port Forwarding: Ensure your router allows traffic on UDP/TCP port 18000, which is the official port for Anno 1800's multiplayer services. 2. Solve "Desync Detected" (LR40) and "Trajan" Errors
Desyncs happen when one player’s game state stops matching the others. This often triggers an "LR40" error.
Verify Game Files: All players must have identical game data. Use the "Verify Files" tool in the Ubisoft Connect or Steam launcher to fix corrupted assets.
Clear the Sync Cache: Delete the Sync Data folder located in your Ubisoft Game Launcher directory (usually AppData/Local/Ubisoft Game Launcher/cache/http2/Default). All players should do this before restarting the game.
Match Version & Mods: Ensure everyone is on the same version (e.g., version 18.4). If using mods, every player must have the exact same mods installed and active. Even a single mismatched mod version will trigger a desync immediately. 3. Stability Fixes for Long Sessions
Long-running multiplayer games can suffer from "lag" when players switch sessions (e.g., moving from the Old World to the New World).
Finding a "fixed" LAN multiplayer experience in typically involves addressing the game's reliance on Ubisoft’s servers even for local play, as the game does not support a native, offline LAN mode. Stability is generally achieved by bypassing third-party launchers like Steam and ensuring all local network configurations are optimized. Core Connectivity Fixes
Most "LAN" issues are actually connectivity conflicts with Ubisoft Connect.
Bypass Steam Invites: Steam's invitation system is often cited as unreliable. Instead, add friends directly on Ubisoft Connect. Launch the game, minimize it, and use the Ubisoft Connect overlay or desktop app to right-click and "Invite to Game".
Enable UPnP: Many desyncs (like the LR40 error) are resolved by ensuring UPnP (Universal Plug and Play) is enabled in your router settings.
Firewall & Subnetting: Ensure both Anno 1800 and Ubisoft Connect are allowed through your Windows Firewall. For local play, verify both PCs are on the same subnet (e.g., both 192.168.1.x) and ideally using IPv4 rather than IPv6. Resolving Synchronization & Lag
Multiplayer in Anno 1800 uses a "lock-step" mechanism where every PC must simulate the exact same game state.
If you're looking for text to use in a guide, forum post, or video to help others fix Anno 1800 LAN/Multiplayer
issues, here are a few options depending on what specifically you fixed. Option 1: The "Desync & Connection" Fix
Use this if the fix involves matching game versions, mods, or Ubisoft Connect settings.
Anno 1800 Multiplayer Fix: Resolving Connection & Desync Issues
If you're unable to join friends or keep getting "LR40" desync errors, follow these steps: Verify Game Files: Ensure everyone is on the exact same version via Ubisoft Connect Sync Your Mods: If using mods, every player must have the exact same mod folders and versions installed. The Anno Union
confirms the game will block connections if setups don't match. NAT Settings:
Check that your Windows Firewall isn't blocking Anno 1800 or Ubisoft Connect. Switching to a "Public" to "Private" network profile often helps. VPN Check:
If playing over a virtual LAN (like Hamachi or Radmin), ensure all players are on the same virtual subnet. Option 2: The "LAN via Virtual Network" Guide anno 1800 lan multiplayer fixed
Use this if you are explaining how to play "LAN" style over the internet using tools like Radmin or Hamachi. How to Play Anno 1800 over LAN (Fixed)
Anno 1800 doesn't have a native "Offline LAN" button, but you can force it using these steps: Launch Ubisoft Connect in Online Mode: The game requires an initial handshake to verify ownership. Join the Same Virtual Network:
Use a tool like Radmin VPN so all players appear on the same local network. Host a Game: Multiplayer menu , select "Host New Game." Invite via Friends List:
Even for "LAN," you typically need to invite players through the Ubisoft friends list. If the "Invite" button is greyed out, restart your Ubisoft Connect client. Option 3: Short "TL;DR" for Discord/Steam Fixed Anno 1800 Multiplayer!
Most issues are caused by mismatched mods or Ubisoft Connect being in "Offline Mode." To fix: Make sure everyone is Online in Ubisoft Connect Disable all mods to test connection. Verify files on Steam/Ubisoft.
If using a VPN/LAN tool, ensure your firewall allows the specific app ports! Key things to remember for Anno 1800 multiplayer: No Speed Controls: You cannot speed up time in multiplayer sessions. Co-op Limit:
You can have up to 16 players in total, divided into 4 factions. Crossplay:
PC players can play across Steam, Epic, and Ubisoft Connect seamlessly. Anno Union for a specific error code like LR40? DevBlog: Multiplayer and Co-op - Anno Union A: No, speed controls are limited to singleplayer. Anno Union Crossplay in Anno 1800 | Ubisoft Help
Anno 1800 supports cross-platform play between Epic, Steam, and Ubisoft Connect. Crossplay is enabled by default. Anno 1800 (PC) Co-Op Information - Co-Optimus
The Evolution and Resolution of Multiplayer Challenges in Anno 1800 For many fans of the grand city-building franchise,
represents the pinnacle of industrial-era strategy. However, since its launch, the multiplayer experience—specifically for those seeking the stability of Local Area Network (LAN) or consistent online sessions—has been a journey of technical hurdles and community-driven workarounds. The Desire for LAN and the "Online-Only" Reality
Historically, the Anno series thrived on local play, but Anno 1800 fundamentally lacks a native, offline LAN mode. This design choice by Ubisoft forced all players through their online servers, making the experience dependent on the stability of Ubisoft Connect. Players have noted that if internet connectivity fails, the multiplayer option typically becomes unavailable, effectively ending any "local" sessions that aren't routed through the cloud. Common Fixes for Multiplayer Connectivity
To "fix" or stabilize the multiplayer experience, seasoned players from the Anno Reddit community and Steam Discussions have identified several essential steps:
Ubisoft Connect Coordination: Rather than using Steam's internal invite system, players often find success by minimizing the game and using the "Friends and groups" tab in the Ubisoft Connect client to send direct invites.
The "Desync" Folder Refresh: A frequent issue involves "Out of Sync" errors. A known community fix involves all participating players deleting the contents of the desync folder located in the Windows user directory for Anno 1800 before restarting the session.
Firewall & Port Management: Ensuring the game is set to bypass firewalls and checking NAT settings (avoiding "Strict" NAT) remains a foundational requirement for stable connectivity. Modern Solutions and Future Outlook Multiplayer not working :: Anno 1800 Community Support
If logs show authentication failures tied to Ubisoft services, or you’ve exhausted all steps above, gather:
If you’d like, I can produce:
Which of those would you like?
While Anno 1800 does not have a dedicated "LAN" button in the traditional sense, you can effectively run a stable local session by ensuring your Ubisoft Connect settings and network configurations are synchronized. Essential Fixes for Multiplayer Stability
If you are experiencing desyncs or connection errors, follow these steps to stabilize your session:
Bypass Steam Invites: Invites sent through Steam are frequently reported as broken. Instead, open Ubisoft Connect, add your friends there, and invite them directly through the Ubisoft overlay (Shift+F2) or by right-clicking their name in the Ubisoft "Friends and groups" list.
Disable IPv6: Many players have resolved immediate connection failures and "LR40" desync errors by disabling IPv6 on their network adapter settings in Windows.
Synchronize Time and DNS: Ensure all players have their Windows "Set time automatically" enabled and have synced their clocks in the date/time settings. Switching to a public DNS like Google (8.8.8.8 and 8.8.4.4) can also resolve server-related handshake issues. For fans of the industrial revolution city-builder, "Anno
Match Mod Folders Exactly: If using mods, every player must have the exact same versions and file structures. The most reliable method is for one player to zip their entire mods folder and send it to everyone else.
UPnP Settings: Check your router settings to ensure UPnP is enabled, as this helps the game manage port forwarding automatically for peer-to-peer sessions. Troubleshooting Common Errors
Anno 1800 LAN Multiplayer Fix Guide
Prerequisites
Step 1: Check Network Configuration
Step 2: Configure Anno 1800 for LAN Multiplayer
-lan argument to the game's executable to enable LAN multiplayer. Right-click on the Anno 1800 shortcut > Properties > Target > add -lan at the end of the target field (e.g., "C:\Program Files (x86)\Ubisoft\Anno 1800\Anno1800.exe" -lan).Step 3: Host and Join a LAN Multiplayer Game
Common Issues and Solutions
Additional Troubleshooting Steps
C:\Users\<username>\AppData\Local\Ubisoft\Anno 1800\logs).Conclusion
The smell of stale coffee and overheating circuitry filled the small apartment. Outside, the rain lashed against the window, a fitting backdrop for the digital storm raging inside.
"It’s the packet loss," Marcus muttered, the glow of the monitor turning his face a sickly shade of blue. "It has to be the packet loss. Look at the jitter."
Elena leaned back in her chair, rubbing her temples. On her screen, the majestic steamships of Anno 1800 were frozen in the middle of the ocean, caught in a glitchy, stuttering dance. "We’ve port-forwarded, Marcus. We’ve hamachi’d. We’ve edited the engine.ini files until the code looked like abstract art. I think the game just hates us."
It was supposed to be a relaxing Saturday. A co-op campaign. Two industrial tycoons building a new world empire together. Instead, for three hours, they had been fighting the notoriously fragile LAN multiplayer handshake. Every time one of them loaded a new trade route, the synchronization would break. Desync Error. The dreaded red text was becoming their screensaver.
"I have one more idea," Marcus said, his voice dropping to a whisper, as if the router could hear him and take offense. "I found a thread on a Czech forum from two years ago. It’s obscure. It involves editing the host file to force a specific tick rate."
"Do it," Elena said, sacrificing her last shred of patience. "Or I’m uninstalling and we’re playing Solitaire."
Marcus typed furiously. The room was silent except for the rhythmic clack-clack-clack of his mechanical keyboard. He was bypassing the standard server browser, forcing the game to look for a local IP address with a brute-force stability patch.
"Okay," he exhaled. "I’m hosting. Look for the session name: Crown Falls Forever."
Elena refreshed the lobby list. Nothing. The list was empty, a void of digital loneliness.
"It’s not showing up," she said.
"Wait," Marcus held up a finger. He tabbed back to his console command center. "The handshake is initiating... it’s pinging... come on, you beautiful piece of code. Acknowledge the connection."
A small ping sound chimed through their speakers.
On Elena’s screen, a single session blinked into existence. Crown Falls Forever. The ping read 8ms.
"Joining," she said, her breath hitching. Verify/repair through Ubisoft Connect or Steam
The loading screen appeared. The bar crawled forward. Usually, at 80%, the game would crash, citing a 'Version Mismatch' or a 'Data Stream Interruption.' But this time, the bar kept moving. 85%... 90%... 99%.
The screen went black for a heartbeat.
Then, the sounds of industry washed over them. The clang of hammers, the hiss of steam pipes, the cheerful cries of the populace. Elena’s camera panned over Crown Falls, the jewel of their empire. The smokestacks were pumping out white plumes, the market squares were bustling, and the trading vessels were sailing smoothly across the bay without a single stutter.
Marcus’s voice came through the in-game chat, crackling slightly but perfectly audible. "Do you see that? Is it real?"
Elena zoomed in on a baker’s stall. The animation was fluid. The NPCs were walking without teleporting. "It’s fixed," she whispered. "It’s actually fixed."
"Prepare the trade routes," Marcus laughed, the tension breaking like a fever. "The Old World needs beer, and I have a fleet of clippers loaded with grain ready to sail."
"No more desync?" Elena asked, testing the waters by rapidly building three consecutive lumberjacks.
"Zero lag," Marcus confirmed. "The connection is solid. We are officially industrialized."
They spent the next six hours glued to their chairs, terrified that closing the game might break the spell. But the connection held. They built skyscrapers, negotiated with the New World, and constructed a monstrous World’s Fair. The rain stopped outside, the sun went down, and the coffee went cold, but inside the digital archipelago of Anno 1800, the economy was thriving, and the empire was finally at peace.
Multiplayer issues in often stem from synchronization errors (LR40) or network configurations that block the game's peer-to-peer communication. Since the game relies on Ubisoft Connect servers for matchmaking even on local networks, "true" LAN often still requires an active internet connection and specific port configurations. Core Network & Connection Fixes
Disable IPv6: Many players find that disabling IPv6 on their network adapter resolves the "unable to connect" error, especially when playing across different Windows versions.
Enable UPnP: Ensure Universal Plug and Play (UPnP) is enabled in your router settings. This allows the game to automatically request the necessary ports, which significantly reduces desyncs.
Prioritize Network Adapters: If your PC has multiple adapters (like Hamachi or VirtualBox), the game may try to connect through the wrong one. Disable any secondary or virtual adapters to force the game onto your primary LAN connection.
Port Forwarding: Manually forward UDP Port 18000 in your router to your PC’s local IP address. Note that routers typically only allow forwarding a specific port to one device, which can cause issues if multiple people are on the same local network. Resolving Desyncs (LR40 Error)
Synchronization errors occur when the game state differs between players.
Uniform Saves: To prevent state mismatches, ensure only the host saves the game. Other players should simply quit without saving when finishing a session.
The "Clean Load" Workaround: If you hit an immediate desync when loading a save:
The host should load the save alone in a single-player session.
Let it run for a few seconds, then create a new manual save.
Quit to the main menu and host a multiplayer lobby using this new save file.
Verify Game Files: Ensure all players are on the exact same game version. In Ubisoft Connect, select Anno 1800 and choose "Verify files" to fix corrupted data that might cause mismatches. Client & Software Fixes
This open-source tool patches the game’s memory at runtime to:
How to use:
anno1800-lan-launcher).Verdict: This is the gold standard for LAN parties. It works even without an internet connection, supports up to 8 players, and has lower RAM overhead than the official method. No desyncs reported in 2026 tests.