How to Fix an All the Magic - Arcana Server That Keeps Crashing
All the Magic - Arcana is a magic-only kitchen-sink built fresh on NeoForge for Minecraft 1.21.1, bringing together Ars Nouveau, Iron's Spells 'n Spellbooks, Malum, and other current-generation magic mods while deliberately cutting out tech and exploration. Because it's built on newer NeoForge 1.21 mods rather than the long-battle-tested 1.12 or 1.16 versions of the same mod families, it can surface mod-specific bugs a little more often than older kitchen-sink packs. Most crash reports trace back to one of a few repeatable causes below, rather than a single mystery bug.
See the All the Magic - Arcana pack page for the full RAM and setup breakdown before you chase anything else.
1. Wrong Java version on boot
NeoForge running Minecraft 1.21.1 requires Java 21. This is the first thing to rule out on any boot failure, especially if your server was previously set up for an older modpack on an older Minecraft version. A Java mismatch typically fails fast and consistently, every single boot, rather than crashing intermittently mid-session.
- Confirm your server is actually launching on Java 21, not Java 17 or Java 8
- Check your launcher/panel's Java path setting if you migrated from an older pack
2. Magic-network tick overload mid-session
Once the server is up and running, the more common failure mode is a crash that happens after a while, usually tied to player activity rather than boot. Arcana combines several major current magic mods — Ars Nouveau, Iron's Spells 'n Spellbooks, Malum — in a single world. Large overlapping magic constructs (dense ritual setups, automated spell casting, high familiar or summon counts) can overload the tick loop in a way that resembles the classic AE2 network tick-overload crash on tech packs, just driven by magic systems instead.
If a crash coincides with a specific player building out a large magic setup, that's the first place to look — scale back the network size or split it across chunks before assuming it's a core bug.
3. Newer mods, less battle-tested edge cases
Because Arcana is built on the newest NeoForge 1.21 versions of these magic mods rather than their long-established 1.12 or 1.16 counterparts, individual mods can have rough edges that older equivalents already worked through. If a crash log consistently names the same mod, check that mod's own issue tracker for a known NeoForge 1.21.1 compatibility fix or update before assuming it's a pack-wide configuration problem.
4. Config or mod-list corruption after a manual change
If you've manually added, removed, or updated a mod outside of a clean reinstall, mismatched config files or stale data from a previous mod version are a common source of crashes that only show up after that change. Reverting to the pack's known-good mod list and configs is the fastest way to confirm whether a manual edit is the actual cause before digging further into logs.
5. RAM under the pack's realistic floor
The real floor for All the Magic - Arcana is 7 GB, not a generic guess based on the mod count alone. Under-provisioning rarely causes an instant, clean crash — what you'll actually see is cascading lag and longer GC pauses as memory pressure builds, which eventually causes a single tick to run long enough to trip a watchdog timeout and crash the server. If your server degrades gradually before it dies rather than crashing outright, check available RAM headroom before anything else.
FAQ
Why does my All the Magic - Arcana server crash right at boot?+
The most common cause on this pack is a Java version mismatch. NeoForge on Minecraft 1.21.1 requires Java 21 — if your host or launcher is still pointed at Java 17 or Java 8 from an older setup, the server will fail immediately. Check your server's Java runtime first before looking at mods.
What causes a 'Ticking Entity' or world-tick crash specifically in this pack?+
Arcana stacks several major current magic mods (Ars Nouveau, Iron's Spells 'n Spellbooks, Malum, and others) in one world. When players build large overlapping magic networks — big ritual setups, spell-casting automation, or dense familiar/summon counts — the overlapping tick load between mods can trigger the same category of crash seen on AE2-heavy tech packs, just caused by magic systems instead of item networks. If a crash log points at a specific mod's tick handler, that mod's network is the first place to scale back.
How much RAM does an All the Magic - Arcana server actually need?+
The verified floor for this pack is 7 GB. Going lower doesn't usually produce a clean, instant crash — it shows up first as rising GC pause times and creeping lag, and only turns into an actual crash once a tick takes long enough to trip a watchdog timeout. If your server feels increasingly sluggish before it dies, RAM headroom is the first thing to check.
Host All the Magic - Arcana on hardware sized for its real floor
All the Magic - Arcana needs a genuine 7 GB floor to avoid GC-driven tick crashes, and taking a backup before any manual mod or config change saves you from having to debug corruption on top of a crash.
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