How to Fix an FTB StoneBlock 3 Server That Keeps Crashing
StoneBlock 3 looks smaller in scope than ATM-class kitchen-sink packs, which leads almost everyone to undersize it — a live boot test confirmed 8 GB simply fails to start the server. Check RAM first; most of this pack's reported crashes trace back to it.
For the full RAM story, see how to host an FTB StoneBlock 3 server or the FTB StoneBlock 3 pack page.
1. RAM below 12 GB — including the 8 GB that simply doesn't boot
This is the first thing to check, not the last. StoneBlock 3 fails to start outright at 8 GB in a live boot test — it isn't a performance issue at that size, the server doesn't come up. 12 GB is the real floor for this pack, regardless of how small its scope looks compared to kitchen-sink packs.
2. Corrupted ironfurnaces-server.toml
Once RAM is confirmed at 12 GB, a startup crash with no obvious cause often traces to a corrupted ironfurnaces-server.toml config file.
Fix: delete it from the config folder and let it regenerate on the next boot. If that doesn't resolve it, some users have needed a full config folder reset.
3. KubeJS NullPointerException ("serverlevel2 is null")
A documented crash in some StoneBlock 3 versions involves a NullPointerException referencing serverlevel2 or KubeJS's playerMap during startup.
Clearing the kubejs/.cache folder has resolved this for some users, though it isn't guaranteed not to recur — check the FTB issue tracker for a patched pack version if it keeps happening after a system restart.
4. Chisels and Bits causing server hangs
Performance problems tied to the Chisels and Bits mod have caused server timeouts in reported cases. If the server seems to hang rather than crash outright, this mod is worth checking before assuming it's a RAM issue (now that RAM is confirmed at 12 GB).
FAQ
I allocated 8 GB and the server won't even start — is that normal?+
Yes, and it's the single most common StoneBlock 3 problem. A live boot test confirmed 8 GB simply fails to start this pack — it looks smaller in scope than ATM-class packs, but it isn't. 12 GB is the real floor.
My server crashes right at startup with no obvious cause — what's next?+
After confirming RAM is at 12 GB, check for a corrupted ironfurnaces-server.toml in your config folder — deleting it lets it regenerate cleanly. If that doesn't resolve it, a full config folder reset is the next step some users have needed.
What does a 'serverlevel2 is null' or KubeJS playerMap error mean?+
That's a documented NullPointerException some StoneBlock 3 versions hit during startup. Clearing the kubejs/.cache folder has helped in some cases, though it isn't guaranteed to prevent recurrence — check the FTB issue tracker for a patched version if it keeps happening.
Host FTB StoneBlock 3 at the RAM it actually needs
CoalHost starts FTB StoneBlock 3 servers at the pack's measured 12 GB floor by default — not the 8 GB that simply fails to boot.
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