LazyDFU Mod Wiki › FAQ
LazyDFU Mod FAQ
10 questions players actually ask, answered.
How do I know if LazyDFU is actually working?
Watch your startup time before and after enabling the mod; the biggest difference shows on slower hardware where the pre-window loading step is longest. If your game still takes the same time to reach the main menu, the mod may not be loading, or your hardware was already fast enough that the skipped step was negligible.
Does LazyDFU break old world conversion?
No. The mod only delays building the conversion rules until a world actually needs them, so when you open an old world the rules are built at that moment instead of at startup. Conversion still happens normally, just later.
Why does my game still take a long time to load with LazyDFU installed?
LazyDFU only skips the world-conversion rule baking step, so other startup costs like mod loading, resource pack scanning, and chunk generation are unaffected. If your startup is dominated by those, the mod will not help much.
Will LazyDFU conflict with other performance mods?
It is extremely small and only touches the datafixer startup path, so conflicts are very unlikely. Mods that also modify startup behavior, like some optimization suites, are the only ones worth testing alongside it.
Do I need to configure LazyDFU after installing it?
No configuration is required; it works as soon as it loads. There are no in-game settings to toggle, so if it is in your mods folder it is already active.
Does LazyDFU work on servers?
Yes, it can be used on the server side to speed up server startup the same way it speeds up client startup. It does not need to be installed on clients for a server to benefit.
What is the datafixer and why does LazyDFU target it?
The datafixer is the system Minecraft uses to convert old world data to the current format, and it normally pre-builds all its rules before the game window appears. LazyDFU stops that pre-building so the rules are only created when a world actually needs converting.
Will LazyDFU make world loading slower when I open an old world?
The conversion work still has to happen, so opening a world that needs converting may take slightly longer at that moment. In practice this is a one-time cost per old world and is usually unnoticeable compared to the startup time saved.
Can I remove LazyDFU later without breaking anything?
Yes, removing it just restores the default behavior of pre-building conversion rules at startup. No world data is altered by the mod, so removal is safe.
Does LazyDFU help on a fast PC?
The benefit scales with how slow the pre-window rule baking is on your machine, so on fast hardware the savings are small. It is most noticeable on weaker CPUs or memory-constrained systems.