How to Fix a Miraculous: Minecraft Server That Keeps Crashing
Miraculous: Minecraft is a Forge 1.20.1 pack built around the Miraculous Ladybug universe — magical jewelry, kwami companions, and a moral framework that lets players run heroic or villain roleplay side by side. Most crash reports for this pack trace back to one of a few well-known patterns: a Java version mismatch on boot, ability-tick load during active transformations and combat, or save corruption from a server that was stopped mid-write. Here's how to work through them in order.
See the Miraculous: Minecraft pack page for the full RAM and setup breakdown before you chase anything else.
1. Java version mismatch on boot
If the server fails before the world even loads, check the Java runtime first. Forge for Minecraft 1.20.1 requires Java 17 — launching it on an older Java 8 or Java 11 install is one of the most-reported causes of an immediate boot failure for packs on this Forge/MC version pairing, and it's the fastest thing to rule out.
- Confirm the startup script points at a Java 17 (or newer) binary
- Check the first few lines of the crash log for a Java/class-version error before digging further
2. Kwami transformation and combat lag under load
Once the server is up, the next common pattern is a crash that only happens with several players active at once. Transforming into a Miraculous hero and fighting adds real per-tick ability and entity overhead — this is a common pattern in franchise-themed ability RPG packs generally, not unique to this one. If tick times start climbing when multiple players transform and fight simultaneously, that's ability load, not a bug in a single mod.
A spark or timings report taken during one of these spikes will usually show the ability/entity-tracking system at the top, which confirms the cause before you start removing mods.
3. Save corruption from unclean shutdowns
The dual hero/villain roleplay system tracks persistent state per player — which Miraculous is equipped, moral-choice progress, and so on. That data gets written to disk regularly, and if the server process is killed (power loss, an out-of-memory kill, a forced stop) mid-write, the result isn't always an immediate error. It can surface later as a delayed crash the next time that player's data is loaded, which makes it look unrelated to the original shutdown.
4. Mod conflicts when extending the pack
If extra mods have been added on top of the base pack, a conflict with the Miraculous ability/entity systems is a plausible source of crashes that don't show up on a clean, unmodified install. This is a common pattern across ability-heavy Forge packs in the 1.20.1 era — custom entity and capability systems can clash with other mods that hook the same player-data or entity-tracking layers. If crashes started after adding a mod, that's the first place to isolate.
5. RAM under the pack's realistic floor
The verified RAM floor for Miraculous: Minecraft is 5 GB. Running under that doesn't usually produce a clean, instant out-of-memory crash — it shows up first as creeping lag and longer garbage-collection pauses as players join and start transforming, which then compounds into a tick timeout and a watchdog-triggered crash. If crashes cluster around peak player activity rather than happening at a predictable moment, check allocated RAM against the 5 GB floor before assuming it's a mod bug.
FAQ
My server won't even boot — where do I start?+
Check the Java version first. Miraculous: Minecraft runs on Forge for Minecraft 1.20.1, which requires Java 17 — running it on Java 8 or Java 11 will fail immediately on boot with a version-mismatch error. Confirm the server is launching with a Java 17 runtime before looking at anything else.
The server is fine at first, then crashes after a while with more players on — why?+
This is usually tick lag, not a hard crash at the code level. Active transformation and combat with Miraculous abilities adds real entity and ability-tick overhead, similar to other franchise-themed ability RPG packs. With several players transformed and fighting at once, tick times climb, the server falls behind, and eventually a watchdog kills it for a frozen tick rather than a clean error.
What's the real RAM floor for this pack, and what happens if I go under it?+
The verified floor for Miraculous: Minecraft is 5 GB. Under that, you won't usually see an instant crash — you'll see creeping lag and longer garbage-collection pauses as more players join and transform, which eventually turns into a tick timeout and a watchdog-triggered crash rather than a clean out-of-memory error.
Host Miraculous: Minecraft on hardware sized for its real floor
Run Miraculous: Minecraft on a server provisioned at or above its verified 5 GB RAM floor, and take a backup before any mod change or config edit so an unclean shutdown doesn't turn into lost player progress.
View Minecraft Hosting →