FAQ

Server Won't Start

"Java not found"

Sea Lantern needs Java to run the Minecraft server. To fix this:

1. Use the built-in Java downloader in Sea Lantern
2. Or install Java manually and restart Sea Lantern — it will auto-detect the installation

Crashes Immediately After Launch

Common causes:

• Java version mismatch: Check that your Java version meets the requirements (see Getting Started)
• Insufficient memory: Try increasing the allocated memory
• Corrupted JAR file: Re-download the server JAR
• Port in use: Check if port 25565 is occupied by another program, or change the port in server.properties

"EULA not accepted"

You must accept the Minecraft EULA on first launch. Sea Lantern will show a prompt — just click accept.

Console Not Responding

Server Seems Frozen

• Check the last log output in the console — it may be loading the world or plugins
• Large worlds may take a long time to load initially
• If truly frozen, use Sea Lantern's safe stop button to shut down the server, then restart

Commands Have No Effect

• Confirm the command format is correct (no / prefix in the console)
• Confirm the server has fully started (console shows Done!)

Can't Connect to Server

Local Connection

In Minecraft, add a server with the address localhost or 127.0.0.1.

• Confirm the server is running and the console shows Done!
• Confirm the client version matches the server version
• If you changed the port, include it in the address, e.g. localhost:25566

LAN Connection

Other players connect using your LAN IP (e.g. 192.168.1.100:25565).

• Make sure you and the other players are on the same local network
• Check that your firewall allows the server port

Internet Connection

Remote players need your public IP or domain name.

• You need to configure port forwarding on your router (forward external 25565 to your local IP)
• Or use a tunneling service (e.g. frp, ngrok)
• Check your firewall settings

WARNING

When exposing your server to the internet:

• Enable online-mode (online authentication)
• Enable the whitelist
• Back up your world regularly

Legacy Windows Workaround

Sea Lantern is built on Tauri 2, which requires Windows 10 (version 1909+) or Windows 11. Windows 7, 8, and 8.1 are not supported.

For users still on older systems, you can install the VxKex extended kernel to supplement the missing runtime libraries and run Sea Lantern on legacy Windows. This method also works for other modern apps that don't support older Windows.

Steps

1. Download Sea Lantern

   • Go to the Download page and get the Windows installer
   • After installation, do not open Sea Lantern yet

2. Download and install the VxKex extended kernel

   • The following is a community fork for Chinese users
   • VxKex-NEXT: github.com/YuZhouRen86/VxKex-NEXT
   • Lanzou Cloud: geekerz.lanzoue.com/b0ra5olfi
   • Baidu Netdisk: pan.baidu.com/s/1w0JUk4JpoKiZQVi2LMoqwA?pwd=0000 (code: 0000)
   • Install it after downloading

3. Enable VxKex for Sea Lantern

   • Right-click the Sea Lantern executable, select "Properties", then the "VxKex" tab
   • Check "Enable VxKex NEXT for this program" and "Report other version of Windows"
   • Click Apply, then OK
   • Sea Lantern should now run on Windows 7
   • All features work except online multiplayer connectivity

Video Tutorial

If you need a visual guide, see this video: VxKex Extended Kernel Installation Guide (Chinese)

Important Warning & Disclaimer

• Using VxKex or other unofficial methods to run Sea Lantern on Windows 7/8/8.1 is not guaranteed to work and may cause various errors and compatibility issues
• The developers will not accept bug reports or fix issues arising from running the software through this method
• Using such methods may pose system security risks — users assume all responsibility
• Upgrading to Windows 10/11 is strongly recommended for the best experience and full feature support
• Sea Lantern is developed and tested on modern Windows systems — legacy Windows compatibility is not officially supported

Other Questions

What permissions does Sea Lantern need?

Sea Lantern needs file system, network, and program execution permissions — these are required for managing Minecraft servers.

Is Sea Lantern safe?

Sea Lantern is open-source software with fully transparent code. It does not connect to any third-party servers, and all data is stored locally.

Which Minecraft versions are supported?

Sea Lantern supports all standard Minecraft server versions — just use the corresponding server JAR file.

How to Back Up the Server?

Server data is stored in the server directory. Key items to back up:

• world/ directory (main world save)
• world_nether/ and world_the_end/ (Nether and End)
• plugins/ directory (plugins and their configs)
• server.properties (server configuration)

TIP

Regular manual backups are recommended, or use an auto-backup plugin.

Server Security

• Enable online-mode=true for online authentication
• Use the whitelist to restrict player access
• Grant OP permissions carefully
• Keep your server software updated to patch security vulnerabilities
• Don't install plugins from untrusted sources

Incompatibility After Version Update

• Always back up before updating the server
• Confirm all plugins support the new version
• Avoid upgrading across multiple major versions at once (e.g. from 1.16 directly to 1.21)
• If issues arise, roll back to your backup