All The Mods2026-06-18 · 8 min read

How to Fix an ATM Server That Keeps Crashing (ATM9 / ATM10)

All The Mods 9 and ATM10 are kitchen-sink packs with 400+ mods. Crashes are usually caused by too little RAM, a wrong Java version, a corrupted chunk, or a mod conflict introduced by a pack update. Here's how to diagnose and fix each.

1

Out of memory

ATM packs need 10–12 GB. Less causes OutOfMemoryError during chunk loading or world generation. Fix: increase server RAM and ensure your JVM flags allocate enough heap: -Xmx10G -Xms4G. Check logs for java.lang.OutOfMemoryError.

2

Wrong Java version

ATM9 and ATM10 run on NeoForge for 1.20.1 and require Java 21. Java 17 causes UnsupportedClassVersionError on startup. Fix: install Java 21 and update the start script to point to it.

3

Corrupted chunk

A broken chunk causes the server to crash whenever anyone moves near it. Fix: find the coordinates in the crash log (at ~X, ~Y, ~Z), use a tool like Chunky or MCEdit to delete that chunk, or delete the region file from world/region/r.X.Z.mca.

4

NeoForge version mismatch after pack update

Updating the server files without re-running the NeoForge installer leaves mismatched loader versions. Fix: re-run the NeoForge installer jar from the updated server pack after every pack update.

5

Mod conflict from a pack update

A new pack version can introduce a mod incompatibility. Fix: check the ATM changelog for the version you updated to. If a specific mod is flagged, remove it temporarily from the /mods/ folder and test.

6

RS or AE2 network corruption

A corrupt Refined Storage or AE2 storage network causes crashes when the chunk loads. Fix: find the network controller coordinates in the log, back up the world, then delete the RS or AE2 grid data files from the world's data folder.

7

Watchdog thread timeout

A frozen tick (usually from a complex automation contraption) causes the server's watchdog to kill the process. Fix: look for 'Considering it to be crashed' in the log, identify the mod causing the long tick from the preceding thread dump, and simplify that automation.

FAQ

What Java version do ATM9 and ATM10 need?+
Java 21. Both packs run on NeoForge for Minecraft 1.20.1, which requires Java 21. Running Java 17 will cause UnsupportedClassVersionError immediately on startup.
What is the minimum RAM for an ATM server?+
10 GB is the practical minimum for ATM9 and ATM10. The packs load 400+ mods and need headroom for chunk generation and late-game automation. 12 GB is recommended for active servers.
How do I find the crash location in ATM logs?+
Search /logs/latest.log or /crash-reports/ for 'at ~' followed by coordinates. The chunk containing those coordinates is usually the source of the crash.
Can a corrupted RS or AE2 network really crash a server?+
Yes, it is one of the most common late-game crash causes in ATM packs. The storage network data lives in the world's data folder, and a corrupt grid file crashes the server every time that chunk loads.
Where are ATM crash logs?+
Check /logs/latest.log for the most recent session and /crash-reports/ for timestamped crash reports with full stack traces.

Host your ATM server from €12/month

CoalHost runs ATM9 and ATM10 with Java 21, NeoForge and auto-backups. Crash detection built in.

View All The Mods Hosting →

Keep reading

Minecraft

Minecraft server.properties Explained — Every Setting in 2026

12 min read

Minecraft

Minecraft Server Keeps Crashing? 10 Common Causes and Fixes

11 min read

Minecraft

How to Install a Minecraft Modpack from CurseForge or Modrinth on Your Server

9 min read