
DatapacksJava
UIM Minecraft - Hotbar Only
Inspired by Old School Runescape's Ultimate Ironman mode, this datapack restricts your inventory and storage options, providing an interesting challenge…
I don't know my version or loader
Open the Minecraft launcher and look at the profile you play on — it names both, like fabric-loader-1.21.4. The version also shows in the bottom-right corner of the game's main menu.
No loader in the profile name? Then it's plain Minecraft, and these mods won't run — you need Fabric or NeoForge installed first.




About
UIM Minecraft is a datapack that restricts your inventory exclusively to the hotbar, while also preventing the storage of your items in chests, and other inventory-containing items.
This pack was inspired by Old School Runescape's Ultimate Ironman mode.
Mechanics
UIM Minecraft aims to restrict any game mechanic that would allow you to indefinitely store an arbitrary item in any way besides your own inventory.
- Your inventory is restricted to your hotbar, offhand, and equipment only. Every other slot is unusable, and attempting to place an item in it will drop the item.
- Chests generated in the world will be locked.
- Furnaces are crafted pre-loaded with coal or a coal block in the centre of the recipe. Once placed, the furnace starts immediately, and pops once it runs out of fuel. This is to allow the smelting of items while making storage in furnaces infeasible. You can also use bamboo, blaze rods, dried kelp blocks, leaf litter, or sticks.
- Minecart chests will be converted into locked barrels.
- Furnaces, smokers, and blast furnaces generated in the world will break upon opening.
- Entities able to hold arbitrary items like llamas and item frames will be killed upon entering interaction range. (Don't worry, elytra in end ships won't despawn.)
- Item frames, chest boats, hoppers, smokers, bundles, and ender chests aren't craftable
- An exception is made for crafters, as you need to make one for an advancement.
Notes
- This pack should work in multiplayer with small groups of people. Beyond that, no guarantees on performance or bugginess.
- This pack kills lots of entities and modifies blocks very easily. Don't use it on an existing world if you value the lives of the llamas, item frames, chests, your inventory, etc. in the world!
- This pack doesn't play nice with barrier blocks.
- Due to the way raytraces are handled in this datapack, sometimes furnaces don't break when running out of fuel or chests don't break upon opening. Avoid aiming at the edges of blocks and swinging your mouse quickly while interacting with these blocks.
Quick facts
- Edition: Minecraft Java
- File type: .jar
- Minecraft versions listed: 1.21.10, 1.21.11
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Modrinth — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — see the MC Java Mods guides for the full walkthrough.
Verified by MCModsHub
- Downloads as UIM-Minecraft-1.21.11-v8.zip
- Download size: 29 KB
- Download link checked 31 Aug 2026 — working
These come from our own check of the pack file, not from the source page.