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Minecraft Snapshot 17w43b

A Minecraft Java Edition snapshot for 1.13

After a very long time in development, we're ready to start snapshots for Minecraft Java Edition: 1.13!

1.13 will be a technical improvement update, intending to both make the game run better for users, and to make it easier for us to add new things in the future. Do not expect any new gameplay features or mechanics in 1.13, as we are trying to stick to improving the game engine for this update.

This first snapshot will bring two major changes to the codebase: Data packs and LWJGL 3.

Data Packs

Usage & Installation

A data pack can either be a zip file or directory inside <world>/datapacks/. For example, both of these are completely valid data packs:

  • <world>/datapacks/
  • <world>/datapacks/SuperPack3000/

If you get a data pack from a friend or the internet, we typically expect that it will just be a zip file. Put it inside the datapacks/ folder and it will be automatically installed.

If you modify, install or remove a data pack whilst the game is running then the /reload command will apply the changes.


  • pack.mcmeta (Required) - Exactly like in resource packs, this contains a description of the pack.
  • data/ - This is what makes it a data pack, containing all data files.
    • <namespace>/ - Much like resource packs, everything needs a namespace.
      • functions/ - Contains all command functions
        • <name>.mcfunction - A command function named <namespace>:<name>
      • loot_tables/ - Contains all loot tables
        • <name>.json - A loot table named <namespace>:<name>
      • structures/ - Contains all world structures
        • <name>.nbt - A structure named <namespace>:<name>
      • advancements/ - Contains all advancements
        • <name>.json - An advancement named <namespace>:<name>
      • recipes/ - Contains all recipes (See note below)
        • <name>.json - A recipe named <namespace>:<name>

Pack Hierarchy

Exactly like resource packs, data packs have a load order. However, there isn't currently a way to see or change this. Sorry! We're working on it. ❤

Note: Recipes?

? Recipes should totally be in data packs, but we haven't finished supporting this yet. For that reason, we don't actively look in custom data packs for recipes, and we also don't synchronize custom recipes from the server to clients.

Basically... they don't work yet. Soooooon!


This isn't a new concept, but I thought I should reiterate what a "namespace" is. Most things in the game has a namespace, so that if we add something and a mod (or map, or whatever) adds something, they're both different somethings. Whenever you're asked to name something, for example a loot table, you're expected to also provide what namespace that thing comes from. If you don't specify the namespace, we default to minecraft. This means that something and minecraft:something are the same thing.

Please always use your own namespace for anything new that you add, and only use other namespaces if you're explicitly overriding something else. Try not to add new things in minecraft, basically.

A namespace should only contain the following symbols:

  • 0123456789 (Numbers)
  • abcdefghijklmnopqrstuvwxyz (Lowercase letters)
  • _ (Underscore)
  • - (Hyphen/minus)

The preferred naming convention is lower_case_with_underscores.

Names of... things...

You can name anything (recipes, advancements, etc) whatever name you like, but these are the only officially supported symbols:

  • 0123456789 (Numbers)
  • abcdefghijklmnopqrstuvwxyz (Lowercase letters)
  • _ (Underscore)
  • / (Forward slash, directory separator)
  • . (Period)
  • - (Hyphen/minus)

The preferred naming convention is lower_case_with_underscores.


We've finally updated to use the newest version of LWJGL. This fixed a lot of long-standing bugs on Mac OS and Linux, and should make for a much more stable playing experience. The biggest benefit you'll experience is that fullscreen mode now defaults to borderless windowed, so that snapping in and out of fullscreen mode is very quick! However, we've already identified the following issues which you may encounter:

  • Fullscreen mode on Mac OS X has a high chance of hard crashing, so we disabled this until we can find a workaround.
  • There may be some cases in the game where key inputs are sent twice, for example pressing a hotbar key whilst hovering over an item in the creative inventory search tab.
  • On Mac OS X, the game icon is no longer a grass block. Again, working on it!

Structure blocks

When you use "save" in a structure block, it now saves it in the following location: generated/<namespace>/structures/<name&gt.nbt.

When you use "load" in a structure block, we try to load from the generated folder before trying data packs. This is so that saving & loading is consistent.

However - please never distribute the "generated" folder as-is if you're making custom maps. Move it all into a data pack. Thank you!

Backwards compatibility - going back in time!

This is always an issue, but we think that we should actually say it this time. We do not officially support going back to old versions of minecraft in the same folder that you run a new version of Minecraft. If you run this snapshot then go back to an older version in the same directory, you will lose all your keybindings.

You are always recommended to run snapshots (and any other version than "the latest release") in their own folders. Incidentally, this is also why your tutorial toasts keep coming back ;)

A word of warning

1.13 will have a lot of experimental snapshots that may break everything and smell funny. This may be one of those snapshots. This is what happens when we're changing all the things!

Install the snapshot

Please report any and all bugs you find in Minecraft to If nobody reports a bug, we can't fix it!

To get snapshots, open your launcher and go to the "launch options" tab. Check the box saying "Enable snapshots" and save. To switch between the snapshot and normal version, you can find a new dropdow menu next to the "Play" button. Back up your world first or run the game on in a different folder (In the "launch options" page).

Snapshots can corrupt your world, please backup and/or run them in a different folder from your main worlds.

Bugs fixed in 17w43b

  • MC-121276 - Loading files from data packs and sounds ignores sub folders (causing e.g. no sounds at all in 17w43a)
  • MC-121286 - No subtitles are showing
  • MC-121290 - Changing languages in the languages menu doesn't have any effect
  • MC-121300 - Default resource pack overwriting custom resource packs
  • MC-121335 - Crash: Invalid escape sequence at line 4 column 37 path $.pack.description
  • MC-121337 - Resource packs do not sort by number

Cross-platform server jar:

Report bugs here:


Nathan Adams
Written By
Nathan Adams

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