How to Fix a Caveopolis 2 Server That Keeps Crashing
Caveopolis 2 is benbenlaw's underground-questing entry in the -opolis series on NeoForge — custom recipes and progression built entirely around caving instead of the surface. Its crash causes follow the same multidirectional-mining pattern as other in-stone and underground-start packs.
See the Caveopolis 2 pack page for the full RAM and setup breakdown before you chase anything else.
1. Server won't boot: check the Java version first
Caveopolis 2 runs on NeoForge, which requires Java 21. A consistent, immediate boot failure with no players online points here first.
- Confirm the server is launching under Java 21, not an older runtime
2. Chunk-load lag from multidirectional cave mining
With progression built entirely around caving, players tunneling in different directions underground is a real, predictable source of chunk-load and lighting lag — the same pattern seen in classic in-stone packs. Several players digging outward from the same starting point at once is where this shows up most.
3. Config corruption or a bad mod update after a pack upgrade
If the server ran fine and only started crashing after updating the modpack version or hand-editing a config, treat that update as the first suspect rather than reopening the Java or RAM questions above.
4. RAM under the pack's realistic floor
The real floor is 6 GB. Below that, multidirectional mining lag from section 2 hits harder because there's no memory headroom to absorb it — expect GC pauses and TPS drift rather than one clean crash.
FAQ
Why does my Caveopolis 2 server fail to boot?+
Caveopolis 2 runs on NeoForge, which requires Java 21. A server on an older Java runtime will fail at startup before any world loads.
Why does my server lag when players mine in different directions?+
Like other underground-start packs, Caveopolis 2 builds its entire progression around caving rather than the surface. Several players tunneling in different directions at once is a real, predictable chunk-load and lighting cost, similar to classic in-stone packs like FTB StoneBlock.
How much RAM does Caveopolis 2 actually need?+
The real floor is 6 GB. Its custom recipes and progression systems built entirely around caving add real overhead beyond a simple vanilla mining experience.
Host Caveopolis 2 on hardware sized for its real floor
Caveopolis 2 needs a real 6 GB floor to absorb multidirectional mining load without tipping into lag, and taking a backup before any risky change keeps a bad edit from costing your progression.
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