How to Fix an FTB StoneBlock 4 Server That Keeps Crashing
FTB StoneBlock 4 is the natural successor to StoneBlock 3, built on NeoForge 1.21.1 with handcrafted Vaults, ancient Echoes, and World Engine progression. The move to a newer loader and the added dungeon-style Vault mechanic are behind most of its crash reports.
See the FTB StoneBlock 4 pack page for the full RAM and setup breakdown before you chase anything else.
1. Server won't boot: check the Java version first
NeoForge on Minecraft 1.21.1 requires Java 21. This is an easy trip point for groups coming from StoneBlock 3 or other Forge 1.20.1 packs, since Java 17 was the right call there and is wrong here.
- Confirm the server is launching under Java 21, not Java 17
- A boot-time failure with no players online points here first
2. Tick spikes when entering a Vault
Vaults in StoneBlock 4 generate and populate a dungeon-style structure the moment a player enters, which is a genuinely expensive, intentional spike built into the pack's progression loop — not a bug. A short freeze or TPS dip right at Vault entry is expected; a crash that happens every single time a specific Vault is entered is worth reporting as a mod issue instead.
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 for StoneBlock 4 is 8 GB. Below that, the Vault-entry tick spike from section 2 hits much harder because there's no headroom to absorb it — expect GC pauses and TPS drift that cluster specifically around Vault runs.
FAQ
Why does my StoneBlock 4 server fail to boot?+
StoneBlock 4 runs on NeoForge for Minecraft 1.21.1, which requires Java 21. A server still running Java 17 — correct for StoneBlock 3 and most Forge 1.20.1 packs — will fail here, since StoneBlock 4 moved to NeoForge.
Why does my server lag or freeze when a player enters a Vault?+
StoneBlock 4's handcrafted Vaults generate and populate a dungeon-style structure on entry, which is a real, intentional tick-cost spike rather than a sign of a bad install. If TPS was healthy right up until the Vault loaded and only dipped briefly, that's expected behavior for this mechanic.
How much RAM does StoneBlock 4 actually need?+
The real floor is 8 GB — higher than the original StoneBlock's 5 GB floor, reflecting the newer loader and the added Vaults/Echoes/World Engine progression systems. Running below that tends to show up as GC pauses and TPS drift during Vault entry rather than a clean crash.
Host StoneBlock 4 on hardware sized for its real floor
StoneBlock 4 needs a real 8 GB floor to absorb Vault-entry tick spikes without tipping into a watchdog kill, and taking a backup before any config change keeps a bad edit from costing a world.
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