Factorio: Reading Server Logs
The **Factorio** log file is the "Black Box" of your dedicated server. Whether you are troubleshooting a startup crash, a mod version mismatch, or the dreaded **Desync Loop**, the `factorio-current.log` holds the answer.
1. The File Location
The active log is always named factorio-current.log. When the server restarts, this file is renamed to factorio-previous.log automatically.
2. Startup Sequence
The first 50 lines of the log show the "Mod Loading" phase. If the server crashes instantly, look here first for "Failed to load mod" errors.
3. Desync Reports
If a "Desync" occurs, the log will generate a path to a specific "Desync Report" zip file. This is crucial for developers to fix bugs.
How to Access the Log
- Navigate to the **Supercraft File Manager**.
- The file is located in the root directory (or sometimes inside
/factorio/depending on install). - Click Edit or View on
factorio-current.logto read it in your browser.
Common Error Code Decoder
| Log Message | The Fix |
|---|---|
Error ServerMultiplayerManager.cpp: "Mod mismatch: Player has X, Server has Y" | The player must sync their mods. Tell them to tick the "Sync Mods with Server" box when joining. |
Address already in use | Port 34197 is blocked. The server is likely already running in a zombie process. Restart the container. |
No such file or directory | The server tried to load a save file (e.g., in `server-settings.json`) that doesn't exist. Check your save name spelling. |
Refusing to start with version X | The map file was saved in a newer version of Factorio (e.g., 2.0) and you are trying to run it on 1.1. Update the server. |
Expert Tip: When reporting a bug to a Mod Author, NEVER copy paste the entire log into Discord. Use a service like Pastebin and link to it. The log usually contains your server IP, so be careful sharing it publicly.
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