Icarus Mods: How to Install Them With Icarus Mod Manager (and on a Dedicated Server)

Icarus mods are .pak files. The game loads them from one folder, Icarus/Content/Paks/mods, with no mod loader and no Steam Workshop. Almost every mod on the community database is built for Icarus Mod Manager (IMM), which merges your chosen mods into a single pak. That makes mods on a dedicated server simple on paper: build the merged pak on your PC, then copy the same file into the same folder on the server.

RocketWerkz doesn't officially support any of this. Their dedicated-server documentation never mentions mods, and the game patches every Thursday. So this guide covers the install, and also what goes wrong in the week after a patch, which is when most modded Icarus servers break.

Pick the right Icarus Mod Manager

Two unrelated programs are called Icarus Mod Manager, and their mods don't work in each other's manager. The CrystalFerrai version says so in its own README.

If a mod page doesn't say which manager it's for, it's almost certainly JimK72's. The rest of this guide assumes that one and points out where CrystalFerrai's differs.

Install mods on your PC first

A dedicated server has no mod browser, so you always build the mod set on a Windows PC and copy it across.

1. Close Icarus. The game must not be running while you install or uninstall mods.
2. Download IMM from Jimk72/Icarus_Software, extract it to a new folder, and run IcarusModManager.exe. Let it install UnrealPak when it asks.
3. Open Download Mod, pick the mods you want, and double-click each one to add it to the install list.
4. Click Install All Listed Mods. IMM merges everything into IMM_Merged_Mod_P.pak and writes it, together with IMM_Merged_Mod.txt, into:

C:\Program Files (x86)\Steam\steamapps\common\Icarus\Icarus\Content\Paks\mods\

5. Launch Icarus. The title screen now shows the checksum notice RocketWerkz added in the Week 94 update (September 2023): "you have mods installed". That notice is expected and means the pak was found.

With CrystalFerrai's manager, drag the .zip files into the window and press Install Mods. Load order is the list order, and if two mods conflict, the one lower in the list wins.

Test the mod set in a solo prospect before you put it on a server. A mod that crashes your client will crash the server too, and on a server you have to read a log to find out why.

Put the mods on your Icarus server

Our Icarus servers run RocketWerkz's Windows server build under Wine, with everything under /home/container. The game folder is laid out exactly as on your PC, so the mods folder is:

/home/container/Icarus/Content/Paks/mods/

1. Stop the server in the panel and take a backup first. Mods that change items or recipes change your prospect saves too, and there's no undo.
2. In Files, go to Icarus/Content/Paks/. Create a folder called mods if it isn't there.
3. Upload IMM_Merged_Mod_P.pak and IMM_Merged_Mod.txt from your PC's mods folder. JimK72 added the .txt file specifically for servers: it lists what's inside the merged pak, so you can always check which mods the server is running. Merged paks can be large, so SFTP is more reliable than the browser uploader.
4. Start the server and watch the console. The panel tails Icarus/Saved/Logs/Icarus.log, so errors show up there live.
5. Join from the PC that built the pak.

Not tested on our servers yet

The folder, file names and upload steps above come from both mod managers' documentation and our server's install layout. We haven't yet confirmed on one of our test servers that the Wine-hosted server loads every mod type. Mods that ship .uasset files (new items, meshes, blueprints) are the riskiest: JimK72's own mod notes warn that "UASSET files may cause dedicated server issues". If a mod works in solo but not on the server, open a ticket with the mod name and we'll look at the log with you.

Does every player need the same mods?

In practice, yes. Keep one merged pak and give the same file to every player. The IMM workflow assumes this: you build one pak and copy it to the server and to your group. Data-table mods (stack sizes, crafting costs, talent points) edit the JSON tables that the game reads from Data.pak. If the server and a client read different tables, you get items that vanish, recipes that disagree, and desyncs. Neither manager documents what happens when a client and the server run different mod sets, and RocketWerkz doesn't either. Don't test it on a live prospect.

Weekly patches and your mods

This is the part an AI summary skips. Icarus gets a "Week N Update" every Thursday (Week 251 went out on 24 September 2026), and each one can change the data tables a mod patches.

• Our server updates itself on restart. AUTO_UPDATE is on by default, so the next restart after a patch pulls the new build. The boot update doesn't run a file validation and leaves your mods folder in place. The problem is compatibility: a pak built against last week's Data.pak can put stale data back into the new build.
• Players update through Steam automatically. Since Week 244 (6 August 2026) the server browser shows only matching-version servers by default, so a server you've held back is invisible to anyone on the new build.
• So update everything together. After a patch, update the mods in IMM, re-merge, copy the new IMM_Merged_Mod_P.pak to the server, then restart. Data-table patches built for CrystalFerrai's manager are designed to survive updates better, because they reference rows by name rather than by position. Even so, rebuild them after every patch.

RocketWerkz's own patch notes blame "leftover mod files" for some of the crash reports they get after updates. If something breaks right after a Thursday, remove the mods first before you look for any other cause.

Troubleshooting Icarus mods

Common Questions

Does Icarus have official mod support?

No. There's no Workshop, and RocketWerkz's dedicated-server documentation doesn't mention mods. What RocketWerkz has done is make core game data easier for modders to reach (2022), and since 2023 the title-screen checksum shows when mods are installed. Mods are community-made and unsupported.

Can I use mods on an Icarus dedicated server?

Yes, the same pak files go into the server's Icarus/Content/Paks/mods folder. Copy the merged pak your PC is using, and keep it identical for every player.

Will mods break my prospect save?

A mod that adds items leaves those items in your saves. Remove the mod later and the items may disappear or break the prospect. Back up Icarus/Saved/PlayerData/DedicatedServer/Prospects/ before you add or remove mods. How to Save in Icarus covers where everything is stored.

Do mods work in Icarus multiplayer without a dedicated server?

Mod managers install into your own game folder, and the same "everyone runs the same pak" rule applies to a hosted session. How to Play Icarus With Friends explains how the two ways of playing together differ.

What to Read Next

• How to Set Up an Icarus Dedicated Server: ports, first boot and where ServerSettings.ini lives
• Icarus Server Settings Explained: tweak rates without mods where you can
• Icarus Console Commands: What Actually Works: admin commands for a modded server
• How to Save in Icarus: back up prospects before changing mods

Made with 💜 by GameServerKings