Space Engineers: Settings, Mods and Sim Speed

Two files - and only one matters for your world

This explains just about every "my settings were reset" case on Space Engineers.

File	When it is used
SpaceEngineers-Dedicated.cfg	The server's own settings: name, ports, admins, auto-restart
Saves/<World>/Sandbox_config.sbc	Your world's settings. This is what the server reads once the world exists

SpaceEngineers-Dedicated.cfg also contains a full <SessionSettings> block with every gameplay setting - but it is only used when the server creates a brand new world. If you already have a world, that block is dead and changes to it do nothing.

The order is: Sandbox_config.sbc beats Sandbox.sbc, which beats <SessionSettings> in the .cfg file.

Note the file extensions too: it is .sbc, not .sav. Guides writing Sandbox_config.sav are wrong.

---

How to change a setting properly

1. Stop the server in the Potionhost control panel and let it finish saving.
2. Delete the file Saves/LastSession.sbl.
3. Edit Saves/<World>/Sandbox_config.sbc under Files.
4. Start the server.

Why delete LastSession.sbl? It remembers which world was last loaded and with which settings. If it does not match <WorldName> in your .cfg, the server can load a completely different save - and it looks exactly as if your changes and your mods vanished.

Never edit the files while the server is running. The server only reads them at startup, keeps everything in memory, and writes memory back on every autosave. Your change is either ignored or overwritten within minutes.

---

The server's own settings

In SpaceEngineers-Dedicated.cfg:

<ServerName>My server</ServerName>
<ServerDescription>Description</ServerDescription>
<WorldName>My world</WorldName>
<ServerPort>27016</ServerPort>
<SteamPort>8766</SteamPort>
<PauseGameWhenEmpty>false</PauseGameWhenEmpty>
<IgnoreLastSession>false</IgnoreLastSession>
<GroupID>0</GroupID>
<Administrators>
  <unsignedLong>76561198000000000</unsignedLong>
</Administrators>

Key	Meaning
ServerPort	The game port, UDP. Default 27016
SteamPort	UDP. Default 8766
Administrators	One <unsignedLong> per admin, holding a SteamID64
Banned / Reserved	Same format as Administrators
GroupID	Steam group ID. 0 means no restriction
PauseGameWhenEmpty	Pauses the world when nobody is online
AutoRestartEnabled	Automatic restart
IgnoreLastSession	Skips the last autosave and uses the config values. A troubleshooting tool - it can cost progress

There is no <ServerPassword>. The password is stored as <ServerPasswordHash> and <ServerPasswordSalt>, and you cannot write it in plain text. Set it through the control panel or the server's own tool.

---

The world's gameplay settings

In Sandbox_config.sbc they live under <Settings>. The most-used ones:

Setting	Default	Meaning
InventorySizeMultiplier	3	How much fits in an inventory
AssemblerSpeedMultiplier	3	Production speed
AssemblerEfficiencyMultiplier	3	Material use in production
RefinerySpeedMultiplier	3	Refining speed
WelderSpeedMultiplier	2	Welding speed
GrinderSpeedMultiplier	2	Grinding speed
MaxFloatingObjects	100	Maximum loose objects in the world
MaxGridSize	0	Maximum blocks per grid. 0 = unlimited
MaxBlocksPerPlayer	0	Maximum blocks per player. 0 = unlimited
TotalPCU	100000	Total PCU budget
BlockLimitsEnabled	-	NONE, GLOBALLY, PER_FACTION or PER_PLAYER
SyncDistance	3000	How far out the world is simulated
ViewDistance	15000	How far players can see
AutoSaveInMinutes	-	Minutes between autosaves
EnableIngameScripts	-	Programmable Blocks. Turn it off if the server lags

Plus the classic on/off settings: EnableCopyPaste, EnableSpectator, EnableJetpack, AutoHealing, ThrusterDamage, EnableSpiders, EnableWolfs, EnableDrones, EnableEncounters, DestructibleBlocks and ExperimentalMode.

AutoSaveInMinutes lives inside <Settings> - not as a standalone line in the .cfg file, as many guides claim.

---

Mods

Mods go in Sandbox_config.sbc in the <Mods> block:

<Mods>
  <ModItem FriendlyName="Definition Extension API">
    <Name>2756894170.sbm</Name>
    <PublishedFileId>2756894170</PublishedFileId>
    <PublishedServiceName>Steam</PublishedServiceName>
  </ModItem>
  <ModItem FriendlyName="Transparent LCD Panels">
    <Name>1913557465.sbm</Name>
    <PublishedFileId>1913557465</PublishedFileId>
    <PublishedServiceName>Steam</PublishedServiceName>
  </ModItem>
</Mods>

Three things have to line up:

• <Name> is <PublishedFileId>.sbm - the ID followed by .sbm
• <PublishedFileId> is the number after ?id= in the workshop address
• <PublishedServiceName> is written Steam with a capital S. Get it wrong and the mod is dropped without an error

The order is the opposite of what you expect

In the file, mods load from top to bottom - the bottom one wins. That is the reverse of the in-game mod list, where the top has the highest priority.

In practice: put frameworks and dependencies at the top, and mods meant to override something at the bottom.

The mod has to be public or unlisted on the workshop. The server cannot download private or friends-only mods.

The server downloads mods itself at startup. To force a mod to download again, delete its folder in the mod cache and restart.

---

The admin tools in-game

If you are on the Administrators list, open the admin panel with Alt+F10. From there you can:

• Enable creative mode, invulnerability and terminal access for yourself
• Use Cycle Objects to walk through every grid sorted by size - your primary tool for finding what is lagging
• Run Trash Removal manually
• Use Entity List to teleport to or delete grids

---

Sim speed - the server's most important number

Simulation speed is the ratio between game time and real time. 1.00 is full speed. Drop to 0.7 and the entire world runs in slow motion for everyone on the server.

The usual culprits, in order:

1. Physics - large grids, lots of rotors and pistons, things stuck inside each other
2. Ingame scripts - one badly written script can take the whole server down. Turn off EnableIngameScripts, or use EnableScripterRole to limit who may run them
3. Loose objects - components from grinding and combat. Keep MaxFloatingObjects low
4. Abandoned grids - the slow killer. Builds from players who quit pile up forever
5. Mods with scripts that run every tick
6. ViewDistance and SyncDistance - the further out, the more has to be simulated and sent

The counter-move is trash removal: TrashRemovalEnabled, BlockCountThreshold, PlayerDistanceThreshold, PlayerInactivityThreshold and StopGridsPeriodMin. Set them up via the admin panel's Trash Removal tab rather than editing the XML.

PCU is not a performance dial. TotalPCU is a budget that protects sim speed. Raising it does not make the server faster - it removes the guardrail that was keeping it running. Remember PiratePCU too, which governs NPC spawns if you run with EnableEncounters.

---

Troubleshooting

Symptom	Likely cause	Fix
The settings were reset	You edited while the server was running	Stop, delete LastSession.sbl, edit, start
Changes to .cfg do nothing	The world already exists, so Sandbox_config.sbc wins	Edit the world file instead
Mods do not load	<WorldName> does not match the world actually being loaded	Check LastSession.sbl and WorldName
Mods do not load (2)	The mod is private or friends-only	It has to be public or unlisted
One mod overrides another incorrectly	The order in the file	Move dependencies up, overriding mods down
MOD PARTIALLY SKIPPED in the log	A corrupt download, or a blueprint added to the mod list	Clear the mod cache and remove non-mods from the list
An item with the same key has already been added	Two mods use the same faction tag	Remove one of them
The server is not in the browser	Wrong ServerPort or SteamPort	Check the ports match the ones you were assigned
The world will not save	A trailing space in the world name, or corrupt entities	Rename the world and clean up via the admin panel
Sim speed decays over days	Debris and abandoned grids piling up	Enable trash removal
The server starts on default values	Invalid XML	Check every tag is closed correctly

---

Good advice

• Change one thing at a time and restart in between.
• Back up Saves/<World>/ before touching the XML. One missing tag can cost you the whole file.
• Keep EnableIngameScripts off until you know who is writing scripts on your server.
• Check sim speed once a week. A slow decline is almost always accumulation - not hardware.
• Turn on trash removal from day one. It is far easier than cleaning up afterwards.

Sim speed dropping and you cannot find the cause? Contact our support and we will take a look with you.