Fix Don’t Starve Together Server Failed to Start

If you see “Server failed to start” when hosting a Don’t Starve Together (DST) game, the problem is almost always a port forwarding, firewall, or mod configuration issue, and it can usually be fixed by checking your network settings and disabling problematic mods. This guide walks you through the most common causes and provides step-by-step fixes that work for both dedicated and in-game hosted servers.

Why Does This Error Happen?

Don’t Starve Together uses a peer-to-peer model for player-hosted games and a client-server model for dedicated servers. When you click “Host Server,” the game tries to open a UDP port (default 10999) so other players can connect. If that port isn’t reachable, the game reports “Server failed to start” even though your computer is running fine. The error can also appear if your game files are corrupted, a mod is incompatible, or your firewall silently blocks the connection.

Check Your Mods First

Mods are the #1 cause of this error in DST. A mod that worked yesterday can break after a game update, or two mods can conflict with each other. Here’s how to test:

1. In the main menu, click Mods.
2. Click Disable All at the bottom.
3. Try hosting a server again. If it starts, re-enable mods one by one until you find the culprit.
4. For dedicated servers, check the mods_settings.lua file in your server folder and temporarily remove all mods entries.

If a specific mod is the problem, check its Steam Workshop page for updates or user reports about the same issue.

Verify Game Files (Steam)

Corrupted game files can also cause startup failures. Steam has a built-in repair tool:

1. Right-click Don’t Starve Together in your Steam library.
2. Select Properties → Installed Files.
3. Click Verify integrity of game files.
4. Wait for the process to finish (it may take a few minutes) and try hosting again.

This checks all game files against the latest version and re-downloads any that are missing or corrupted. It won’t delete your saves or mods.

Port Forwarding and Firewall

If mods and file integrity are fine, the next suspect is your network. DST uses UDP port 10999 by default (you can change it in the server settings). You need to forward this port to your computer’s local IP address. Here’s what to do:

• Find your local IP (Windows: ipconfig in Command Prompt; Mac: ipconfig getifaddr en0 in Terminal).
• Log into your router’s admin page (usually at 192.168.1.1 or 192.168.0.1) and look for “Port Forwarding.”
• Create a new rule: UDP protocol, external port 10999, internal port 10999, and your computer’s IP address.
• Also add an exception in Windows Defender Firewall or your third-party firewall for the game executable (both dontstarve_steam.exe and dontstarve_dedicated_server_nullrenderer.exe).

If you’re on a college campus or a network you don’t control, you may not be able to forward ports. In that case, consider using a dedicated server hosting service or a VPN that supports port forwarding.

Dedicated Server-Specific Issues

Running a dedicated server (via the dontstarve_dedicated_server_nullrenderer executable) has its own pitfalls:

• Make sure you’ve launched the game at least once to generate the required cluster files.
• Check that your cluster.ini and server.ini files have the correct settings (e.g., game_mode = survival, max_players = 6).
• If you’re using a command-line startup, ensure you pass the correct -conf_dir and -cluster arguments.
• Look at the server log file (My Documents/Klei/DoNotStarveTogether/Cluster_1/Master/server_log.txt) for the actual error message. It often says something like “Port 10999 is already in use” or “Failed to bind socket.”

Common Misconception: “It’s a RAM Issue”

Many players think the error is caused by insufficient RAM. While DST can use a few gigabytes of RAM, the “Server failed to start” error is rarely about memory. If you were truly out of RAM, the game would crash or freeze, not show a clean error message. The error is almost always network-related or mod-related. That said, if you have less than 4GB of RAM, you may experience other performance issues, but that’s not what this error means.

When All Else Fails: Reset Your Configuration

If you’ve tried everything above and the error persists, your server configuration files may be corrupted. The easiest fix is to reset them:

1. Close the game completely.
2. Navigate to Documents/Klei/DoNotStarveTogether (Windows) or ~/Documents/Klei/DoNotStarveTogether (Mac).
3. Rename the Cluster_1 folder to Cluster_1_backup (or delete it if you don’t need your world).
4. Launch the game and create a new server. This will generate fresh configuration files.

If the new server starts, you can copy your save files from the backup into the new folder if you want to keep your world. This nukes almost all configuration-related problems.

Frequently Asked Questions

How do I change the default port?

In the server settings when hosting, you can set a custom port under the “Network” tab. For dedicated servers, edit the server.ini file and change the server_port value. Remember to forward the new port on your router.

Can I host a server without port forwarding?

Yes, but only if you use a service that provides a relay or tunnel. Some VPNs offer port forwarding, and there are third-party tools that can help, but the simplest solution is to use a dedicated hosting provider that handles the networking for you.

Why does it work for other players but not me?

If your friends can host but you can’t, the issue is specific to your network or installation. Check your firewall, router, and whether your ISP uses Carrier-Grade NAT (CGNAT), which prevents inbound connections. You can test by trying to host a game in another game that uses the same port type.

Does the error appear on both Windows and Mac?

Yes, the error appears on all platforms, but the troubleshooting steps are slightly different. On Mac, the firewall settings are under System Preferences → Security & Privacy → Firewall. The file paths also differ (as shown above).

What if the error says “Port already in use”?

Another program is using port 10999. You can find out which program with netstat -an on Windows or lsof -i :10999 on Mac. Then either close that program or change DST’s port to something else.

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