Core Keeper Server Troubleshooting
This checklist separates the problems that look alike: an old Game ID, a stopped dedicated-server process, a version mismatch, a blocked network, a bad save, and a mod that no longer loads. Start with the smallest reversible test and keep the world backup untouched until the group can join again.
Last verified: September 1, 2026. Use the Game ID connection guide for a player who types a value and sees no response. Pugstorm's official FAQ is the source for the supported join flow and save locations.
Quick triage table
| Symptom | Likely boundary | Safe first test |
|---|---|---|
| Nothing happens after entering a “password” | Wrong join method or stale Game ID | Open Join Game, restart the Dedicated Server tool, and enter the newly printed Game ID. |
| Join begins but never finishes | Build mismatch or network path | Update Steam and the Steam Tools app, then test once from the same network and once externally. |
| Only one platform cannot join | Platform support | PC storefronts can play together; the FAQ says PC/console cross-platform crossplay is unavailable. |
| World fails after a mod or update | Changed content or save state | Restore the clean backup and reproduce without mods before changing files again. |
| Everyone reports lag after a patch | Version or world-load regression | Record the build, player count, world size/progression, and server log; do not claim a universal RAM or port fix. |
Connection and Game ID checks
- Launch Core Keeper Dedicated Server from Steam > Tools.
- Choose Launch Dedicated Server, click Play, and wait for the command window to print a Game ID.
- Keep the process running while the player chooses Join Game and enters that current ID.
- Restart both client and server if the ID was copied before initialization finished.
The official dedicated-server announcement says the supported flow does not require port forwarding. A local firewall, VPN, filtered network, or CGNAT can still affect a particular connection; compare local and external tests and capture the result rather than opening arbitrary ports.
Version and platform checks
- Update the game and Dedicated Server tool together after an official patch.
- Have players fully restart Steam and Core Keeper so an old process is not holding a stale build.
- Keep all clients on the same PC storefront family when testing. Cross-platform PC/console play is not supported by the current FAQ.
- Test a vanilla copy before investigating Workshop items or community mods.
World backups and recovery
Back up before moving, deleting, or repairing files. Pugstorm lists these locations:
| Data | Windows | Linux |
|---|---|---|
| Player saves/backups | C:\Users\[USERNAME]\AppData\LocalLow\Pugstorm\Core Keeper\Steam\[STEAM ID] | ~/.config/unity3d/Pugstorm/Core Keeper/Steam/[STEAM ID] |
| Dedicated worlds | C:\Users\[USERNAME]\AppData\LocalLow\Pugstorm\Core Keeper\DedicatedServer\worlds | ~/.config/unity3d/Pugstorm/Core Keeper/DedicatedServer/worlds |
- Stop the server cleanly with
q. - Copy the relevant directory to a dated backup location.
- Try the most recent known-good copy on the current server build.
- Keep the original untouched until players have joined, saved, and rejoined.
Performance and patch-lag evidence
Do not paste an invented server.cfg, player-limit key, or universal port into a Core Keeper support answer. Instead record CPU/memory/disk usage, player count, explored-world size, mod list, build numbers, and the exact time a save or area load stalls. A recent community patch-lag report is a useful lead, not proof of a general regression.
Mod isolation
- Disable all mods and confirm the clean world joins.
- Restore one mod at a time from the documented mod/Workshop workflow.
- If a mod breaks startup or joining, revert the newest change and check its current game-build requirements.
- Keep a written mod list and backup so another admin can reproduce the test.
Evidence to collect before asking for help
- Game and Dedicated Server build numbers.
- Fresh Game ID timestamp and the exact Join Game screen used.
- Whether local and external players fail in the same way.
- Server console output, client logs, and the last successful save time.
- World backup identifier, mod list, and the first step that changed the outcome.
Related Core Keeper guides
- Dedicated server setup
- Game ID and connection troubleshooting
- Mods and Workshop rollout
- Admin and chat commands
- Server cost and sizing
Need fewer home-network and process variables? Use managed Core Keeper hosting with an always-on process and backups, while keeping this evidence-first workflow for mods and updates.