How to Install Mods on an Abiotic Factor Server

Official vs unofficial mods after v1.5.0

Abiotic Factor build 1.5.0.31459 added official mod support through mod.io on Steam, PS5 and Xbox/PC App, with a later hotfix for console mod browser issues. For server owners, that changed the process completely: the server can advertise its mod list, and joining players get a one-click install prompt in game. That is why many older guides are now wrong for normal server modding; they describe the old manual UE4SS and pak workflow, not the supported server path.

Use this comparison first, because it decides how much work lands on you and how much lands on your players.

The official route is simpler because the server tells each client exactly which IDs to fetch, instead of you chasing mismatched files across several machines.

Before you start: protect the world and check the easy options

Back up the whole world save before you add or remove a mod. If you did not change -WorldSaveName, the default world folder is Cascade, and that is the folder to copy. Do not back up just the obvious save data and miss SandboxSettings.ini, because that file lives inside the world save too.

• Check sandbox settings first. Many common changes already exist as built-in sandbox settings, including things like stack size, XP, item weight and enemy spawns. Built-in settings do not need client downloads, do not create load-order issues, and do not get blocked by mod version checks after a patch, so they are usually the cleaner server choice.
• Update the server before modding it. Official mods are version-checked against the current game build. If the server is behind, you can end up diagnosing a version problem as if it were a mod problem. If you update through SteamCMD, the dedicated server app is 2857200 and a validate pass helps ensure the server files match the current build.
• Add one mod at a time. This costs you a few extra restarts, but it keeps cause and effect readable. When two mods fail together, you do not know whether the issue is dependency, order, version or the mod itself.
• Make sure the base server already works. If you are still setting up the machine, sort the normal dedicated server first with our guide to self-hosting a game server, then add mods after the plain server is stable.

Method A: self-hosted server with RunServer.bat

If you run the official Windows dedicated server yourself, use launch parameters in RunServer.bat. That keeps the mod list in one place, lets the server fetch the right packages at startup, and gives you a clear log if something fails.

Step by step

1. Stop the server fully. Do not edit a live process. A full stop clears any half-finished download state and makes the next log easier to read.
2. Open RunServer.bat and find the line that starts AbioticFactorServer-Win64-Shipping.exe.
3. Get your mod.io personal access token from your mod.io account Access page. Keep it secret. This is what the server uses for proper mod downloads and dependency handling.
4. Copy each mod’s “# ID” from its mod.io page. The server wants IDs, not the mod title.
5. Add both mod parameters to the launch line: -ModioToken=YOUR_MODIO_TOKEN and -Mods= followed by the IDs separated with semicolons. Leave no space after the equals sign.
6. Save the file and start the server. On first boot, give it time to download and mount the mods.
7. Watch the log. The server log is the first place to check for missing dependencies, version blocks, or mount failures, and it usually tells you how to fix the problem.

AbioticFactorServer-Win64-Shipping.exe -log -newconsole -useperfthreads -NoAsyncLoadingThread -MaxServerPlayers=6 -PORT=7777 -QueryPort=27015 -ServerPassword=YourServerPassword -SteamServerName="Your Server Name" -ModioToken=YOUR_MODIO_TOKEN -Mods=6472275;6472552;6456360

Why the token matters: without a token, the documented behaviour is that the server re-downloads its mods every time it starts. That wastes bandwidth, slows boot, increases disk churn and makes timeouts more likely. With a token, the server can also pull missing dependencies for the mods you listed; without it, you need to list dependencies yourself or the server may start with an incomplete set.

How to tell it helped: on the next restart, the server should stop fetching the same mods again from scratch, and the log should show a cleaner startup with fewer dependency complaints. If you still see repeated fresh downloads on every boot, treat that as a token problem first.

Method B: rented server panel

Many rented panels expose the same official mod.io settings as fields rather than raw launch parameters. Expect a mod.io token field, a Mod IDs field, and sometimes a use subscribed mods option or a Collection ID field.

1. Stop the server first. Many panels only rewrite startup options on a full restart. Editing while it is running can leave the old process using the old mod list.
2. Paste your personal mod.io token into the token field.
3. Enter the mod IDs in the Mod IDs field, separated with semicolons.
4. Keep the order deliberate. The first ID loads first, so if two mods touch the same content, order can decide which result wins.
5. If your panel offers subscribed-mods or a collection option, use one clear method. Mixing several panel systems at once makes it harder to tell where a wrong ID or stale cache is coming from.
6. Start the server and read the console or log output. You are looking for successful downloads, successful mounts and any version warnings.

The panel is only a front end for the same server behaviour. A token still matters for dependency resolution and for avoiding repeated downloads, and the ID order still matters for load order. If the panel has file access as well, that is useful later for backups and advanced sideloading, but it is not required for a normal official mod.io setup.

What players need to install to join

For official mod.io mods, your players normally do not install anything by hand. They join the server, see the server’s mod list, and the game prompts them to download and install those mods with one click. The client is being told exactly what the server requires, which is why this route causes fewer version mismatches than manual file mods.

If a player cannot join a modded server even though the mod list is correct, the first fix is simple: open Abiotic Factor > Mods on the main menu, accept the mod.io terms, then try again. This is a common join blocker on otherwise healthy official modded servers.

Local Only cosmetic mods are different. These are personal client mods that can be used on any server, and other players will see default cosmetics unless they also have the same mod. If you want to allow that, keep AllowLocalOnlyMods enabled in the world’s SandboxSettings.ini; if you want the cleanest support path, turn it off so everyone joins with only the server-declared set.

Console players can use the official mod.io path only. They cannot install UE4SS or pak files manually, so a server that relies on legacy unofficial mods becomes a PC-only server in practice.

Load order, dependencies and version checks

Most “modded server broke after an update” reports come down to three rules: order, dependencies and version gates. None of these are about raw FPS; they are about what data gets mounted, in what sequence, and whether the game allows that mod version to load at all.

This update-day timeline is the bit to keep in your head before you touch a live save.

• Order of IDs matters. The first ID loads first. If two mods change the same thing, the order can decide which change wins. The trade-off is simple: a longer stack gives you more combinations, but it also gives you more chances for one mod to cancel part of another. If a change appears to do nothing, check order before assuming the mod is dead.
• Dependencies matter even more when you skip the token. With a token, missing dependencies of your listed mods can download automatically. Without a token, you must list dependencies yourself, because the server only knows about the IDs you explicitly provided. If a required dependency is missing, the server may fail to mount the full set or may start with incomplete behaviour.
• Official mods are version-checked after every game update. A mod built for an earlier game version cannot be enabled until its author updates it, so official mods are disabled automatically after a game update until that happens. That is a safety check: it stops old data loading against a changed game build and turning a version mismatch into a corrupted world or crash.

What to do on update day: update the server first, start it once, read the log, then remove any not-yet-updated mod ID temporarily if it is blocking the server. That gets the world booting again, but the trade-off is important: if you disable or remove a mod on an existing save, its items and deployables are removed from that save and stability is not 100% guaranteed. That is why the backup comes first, not after.

Advanced options: sideloading, custom mod folders and timeout control

Most people should stop at official mod.io IDs plus a token. The settings below are for tighter admin control, awkward host layouts, or provider-style workflows.

Sideloading with -SideloadMods

-SideloadMods tells the server to skip mod.io downloading and mount pre-downloaded mods from disk instead. It is mainly there for game server providers, and support is limited. You still need -Mods= with the mod IDs, because the IDs tell the server what to mount and what to advertise to clients when they join.

AbioticFactorServer-Win64-Shipping.exe -log -newconsole -Mods=6472275;6472552;6456360 -SideloadMods -SideloadModsPath=AbioticFactor\Mods

By default, the sideload path is AbioticFactor\Mods, and each mod needs its own folder named after the mod ID. Use the mod’s Windows Server file from mod.io when you prepare sideloaded content. This can reduce repeated startup downloads and gives you tighter disk control, but the trade-off is that you now own the update process for those files.

Changing the download folder with -ModsDir

-ModsDir= changes the mod.io download folder and requires a token. The default is AbioticFactor\Saved\mod.io. This does not improve runtime performance by itself; it is mainly about disk organisation, host file layout and making cached downloads easier to manage.

Slow downloads and -ModInstallTimeout

-ModInstallTimeout controls how long the server waits for mod downloads before it fails startup. The default is 900 seconds. This setting costs startup time, not gameplay performance, so only touch it when the server is failing during downloads rather than during gameplay; do not confuse a slow first install with a broken mod.

-OverrideModWarnings

-OverrideModWarnings bypasses mod warnings that would normally stop the server starting. Use it only if you already know exactly why the warning is safe to ignore. It can get a server past a guard rail, but the trade-off is that you may turn a clean refusal into a crash or a damaged save.

Legacy UE4SS and pak mods: only if a mod still works with 1.5.0

Use the legacy route only when an old mod still works with v1.5.0 and there is no official mod.io version to replace it. Deep Field expected nearly all unofficial mods to break with the Modding Update, they do not appear in the in-game browser, and the game offers no support for them.

UE4SS on a dedicated server

• Put version.dll and the ue4ss folder in AbioticFactor\Binaries\Win64\.
• Do not use dwmapi.dll on the dedicated server; that is for the client.
• Lua mods go in AbioticFactor\Binaries\Win64\ue4ss\Mods\ and each need a line such as ModFolder : 1 in mods.txt (or an enabled.txt file in the mod folder). Check UE4SS.log after the first start.
• Some hosts running the Windows server under Proton on Linux report UE4SS not loading at all.

Pak and LogicMods

• Put .pak, .ucas and .utoc files in AbioticFactor\Content\Paks\.
• Leave the game’s own pakchunk0-WindowsServer and other global files alone.
• Blueprint LogicMods go in AbioticFactor\Content\Paks\LogicMods\.
• Every player needs the same files on their PC, or they will not see the same behaviour.

Why legacy mods break so often: they patch game data directly and v1.5.0 changed the game files and code they patch. That makes them sensitive to changed file layouts, changed hooks and changed version expectations. The admin cost is higher too: every client must match exactly, consoles cannot join, and a Fatal Error after an update often means stripping all unofficial mod files first and, in stubborn cases, doing a clean reinstall because leftovers can remain after uninstalling.

Troubleshooting a modded server

Split the problem early. If you are using official mod.io IDs, think in terms of token, dependency, order and version checks. If you are using legacy file mods, think in terms of missing client files, broken hooks and leftover unofficial files after an update.

Which install method fits you?

If you are choosing a provider for a modded server, look for a proper mod.io token field, a clear Mod IDs field, file access for sideloading, simple backups, and a Windows server option if you rely on UE4SS. That short list matters more than fancy extras. Our Abiotic Factor server hosting comparison is the place to narrow that down.

Abiotic Factor server FAQ

Does Abiotic Factor have official mod support?

Yes. Since v1.5.0, Abiotic Factor has official mod support through mod.io, including dedicated server support where the server declares the required mod IDs and players get a one-click install prompt on join. For server owners, that is now the default path unless you deliberately choose a legacy unofficial mod.

Do my friends need to install the mods to join my server?

For official mod.io mods, they do not need to copy files by hand. They join, see the server’s mod list, and the game offers to download and install the required mods automatically. For legacy UE4SS or pak mods, every PC client must install matching files manually.

Can console players use mods on an Abiotic Factor server?

They can use official mods delivered through the supported mod.io system. They cannot use legacy UE4SS or pak mods, because those rely on manual file installs that consoles do not expose. So if you want a mixed PC and console group, stick to official mods.

Why does my server download its mods every time it starts?

The usual cause is that the server is missing -ModioToken or the panel token field is blank. Without a token, the documented behaviour is repeated re-downloads on startup. Adding the token also helps the server pull missing dependencies instead of making you list every one manually.

Will removing a mod break my Abiotic Factor world?

It can. The game allows mods to be disabled on an existing save, but the mod’s content is removed and stability is not guaranteed, so items and deployables from that mod usually disappear. That is why you back up the Cascade world before changing the mod list, not after.

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