How to Fix “Failed to Load Datapacks, Can’t Proceed With Server Load”

Direct answer

Failed to load datapacks is usually the final summary, not the root cause. Read the exception immediately above/below it for the specific datapack, registry, missing entry, mod, or world-generation setting that failed. Fix or update that component on a backup/test copy.

Common causes

A datapack was written for a different Minecraft data format/version.
A mod that contributes registries/worldgen is missing, disabled, or the wrong version.
A datapack file referenced by the world was removed or corrupted.
Custom dimension/worldgen data is invalid for the current Minecraft release.

Use changes in reverse order

If the server worked before a mod/datapack update, stop it, take a backup, and revert the most recent change first. For modpacks, restore the exact server-pack version rather than mixing individual updated mods.

Focused diagnostic check: Identify the pack named in the first error. Make a full world backup, then inspect world/datapacks for that pack and compare its declared data-pack format and the server version. If it supplies world-generation dimensions or custom registries, do not remove it from the only copy of a production world; test a restored copy first.

About --safeMode

Treat safe mode as a diagnostic tool.

The server may offer --safeMode to load only vanilla datapacks. That can help confirm that custom data is the cause, but do it on a backup/test copy and do not casually save a production world that depends on custom dimensions or registries while those packs are absent.

If the error follows a world upgrade/downgrade

Check for a newer-world data-version error and restore the correct backup/version. Registry and datapack failures can be symptoms of incompatible world data rather than a standalone ZIP in datapacks/.

Official references

These references were checked while preparing this fix. Version-specific behavior can change, so use the project documentation for your exact release when a detail differs.

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