How to Fix a Society: Sunlit Valley Server That Keeps Crashing

1. Check your Java version first

Forge 1.20.1 requires Java 17. If the server won't boot at all — it exits immediately or fails before the world even starts loading — a Java version mismatch is the single most common cause and the first thing worth ruling out, before looking at mods, RAM, or anything else. This is a universal requirement for any Forge pack on 1.20.1, not something specific to this pack, but it's easy to overlook if you're reusing an older Java 8 setup from a legacy 1.12.2 server.

• Confirm the server is launching with Java 17, not Java 8 or Java 11
• If the boot failure happens instantly with no log output, this is the first thing to check

2. RAM headroom — this pack runs lean, which cuts both ways

Society: Sunlit Valley is one of the lowest RAM-floor packs in the catalog. That's a deliberate design choice for a low-pressure, no-automation pack, but it means there's very little slack built in. Adding a large resource pack, shaders, or a few extra quality-of-life mods on top of the base 4 GB floor tends to push memory usage over the edge faster than you'd expect for a pack that otherwise feels light.

When RAM runs short, the symptom usually isn't a clean, instant crash. It's lag that gradually gets worse, garbage-collection pauses that stretch out tick time, and then eventually a tick timeout kills the server. If your crashes are preceded by a few minutes of growing lag rather than happening out of nowhere, RAM pressure is the most likely explanation.

3. World-save or tile-entity corruption after an unclean shutdown

Farming-heavy packs like this one lean on Farmer's Delight for cooking and food mechanics, which adds a meaningful number of custom block entities — cooking pots, cutting boards, and similar — on top of vanilla crops and storage. This isn't a mod-conflict issue so much as a generic Forge pattern: if the server is killed mid-autosave (a host crash, an out-of-memory kill, a forced stop), the region file being written at that moment can end up partially corrupted. Packs with more block-entity data per chunk are a little more exposed to this than a plain vanilla world, simply because there's more state being written on each save.

If a crash consistently points back to chunk or tile-entity loading near a specific area of the map rather than happening pack-wide, this is worth checking before assuming it's a mod problem.

4. Quest data getting edited or touched while the server is live

The custom quest system is one of the more stateful parts of this pack, and quest progress files are generally not safe to hand-edit while the server is running. If you or another admin opened a quest save file directly (rather than through in-game tools) while players were online, a write collision on that file is a plausible — and avoidable — source of an otherwise unexplained crash or corrupted save on next boot. The fix is procedural rather than a mod fix: stop the server before touching any quest or progress files directly.

5. RAM under the pack's realistic floor

The real floor for a stable Society: Sunlit Valley server is 4 GB — lower than many packs in the catalog, which tracks with how light the base pack is designed to be. Running under that floor doesn't usually produce a single clean crash message. What you'll actually see is lag and GC pauses creeping in as the heap fills, then a tick timeout once the server can't keep up with the game loop. If crashes seem to cluster during busier moments — more players online, more chunks loaded, a resource pack added on top — check that the server is actually provisioned at or above the 4 GB floor before looking anywhere else.