Valheim Community Patch

Vanilla bug fixes and performance fixes. No gameplay changes.

This mod exists to fix things that are broken or pathologically slow in Valheim itself — crashes, exceptions that silently kill a system, item loss, quadratic hot paths, per-frame allocations, log spam. It deliberately ships no quality-of-life features, no balance changes, and no content, so you can install it on a server without anyone having to agree about how the game should play.

Performance fixes are always on; the config holds only their tuning values and the admin-only Verify diagnostics. Correctness and terrain fixes each have their own toggle. Config values are admin-only and server-synced.

Each fix is tagged with the side it is worth installing on. (server) fixes only do something on the machine hosting the world — a dedicated server or a listen host. (client) fixes need a local player, and are not even applied on a dedicated server, which is why the startup log there reports a smaller number. (both) fixes do work wherever they are installed. A one-sided install is safe; it just gets you a subset. See Installation.

Why so many fixes are client-side

A Valheim dedicated server is not a simulation host. It only creates game objects inside its own active area, and a headless server never has a player to anchor that area to, so that area stays at world origin for the whole run. Creatures, fires, chests, tar pits and everything else near a player are created, owned and simulated on that player's client; the server holds the data and relays it.

So the fixes a server gains from are the data-and-network ones — ZDO handling, world load, packet allocation, socket logging — and almost everything else is worth having on the client.

Performance Side by Side

Terrain Fix comparison

Terrain Tears	Terrain Fixed

Fixes in this release

Where a fix was sourced from, or corroborated against, another modder's work, that is recorded per fix under Credit and sources.

Performance

• Fix Portal Connection Scan (server) — pairs portals through a tag index instead of rescanning every portal for each unconnected one every five seconds.
• Fix World Load Connection Scan (server) — indexes the world-load pairing of portals, spawners and sync transforms with their targets instead of comparing every pair.
• Fix Disconnect ZDO Sweep (server) — indexes non-persistent objects by owner, so a disconnect sweeps only the departing player's objects instead of every ZDO in the world.
• Fix Tar Pit Buffer Disposal (client) — disposes tar pit raycast buffers only when they were allocated, so a tar pit whose load failed cannot throw out of scene teardown.
• Fix ZDO Packet Allocation (both) — writes one network package into another straight from its buffer instead of copying the whole payload onto the heap first.
• Fix Mist Query Overhead (client) — answers mist volume queries from a zone-bucketed snapshot and heightmap data instead of scanning every mist volume with native reads and physics rays per particle.
• Fix Heightmap Lookup Scan (both) — finds the terrain tile under a point with a zone-keyed lookup instead of scanning every loaded tile.
• Fix Static Object Ground Checks (both) — reads a tree or rock's position once per ground check instead of about six times.
• Fix Grass Rebuild Burst (client) — spreads a whole-area grass rebuild over a few frames, nearest patches first, instead of regenerating every patch in one frame.
• Fix Terrain Builder Throughput (both) — makes the terrain build thread sleep only when idle and hold more finished results.
• Fix Zone Collider Stall (client) — bakes the terrain collider of an already-generated zone on a background thread instead of the main thread.
• Fix Prefab Query Scan (both) — answers "every object of this prefab" from an index instead of scanning every ZDO in the world.
• Fix Grass Ground Raycasts (client) — reads the ground height, slope and biome for grass placement from terrain data instead of casting a physics ray per blade.
• Fix Background Zone Pacing (server) — defers background zone pre-generation by a tick when the previous frame ran long or the last generation was expensive (both configurable).
• Fix Water Material Lookup (client) — caches each water tile's surface material instead of fetching it from the engine every frame.
• Fix Distant Terrain Hitch (client) — rebuilds the far-terrain ring a few tiles per frame (configurable; 9 is vanilla) instead of all nine at once.
• Fix Idle Scene Sweep (both) — skips the 30 Hz object create/destroy pass when cheap change-tracking proves nothing changed, keeping one full pass per second as a safety sweep.
• Fix Support Lookup Cost (both) — resolves which building piece owns a collider through a lookup table instead of a hierarchy walk per collider.
• Fix Light Flicker Overhead (client) — stops updating torch flicker beyond a configurable distance, and exposes the game's dormant point-light cap as a client-local "Point Light Limit" (-1 is vanilla).
• Fix Piece Event Stall (both) — registers building pieces for terrain-rebuild cache clears in a per-heightmap table instead of an event whose subscribe copies and unsubscribe scans the whole list.
• Fix Unload Sweep Cost (both) — runs the object-unload sweep on a configurable wall-clock interval (default 100 ms) instead of on every pass.
• Fix Spawn Queue Churn (both) — keeps the sorted spawn backlog between frames instead of rebuilding and re-sorting it thirty times a second.
• Fix Object Stream Rescan (both) — keeps the set of objects waiting to spawn as a running queue fed by the events that change it, instead of rediscovering it from every zone around you thirty times a second.
• Fix Zone Occupancy Scan (both) — answers whether a zone still holds objects from a per-zone tally instead of walking every loaded object.
• Fix Piece Material Polling (both) — waits for a piece's random material seed on one shared ticker and stops polling once the values are applied.
• Fix Idle Support Checks (both) — lets a building piece skip its structural support re-check until a neighbour is built, destroyed or changed or the terrain is edited; "Support Change Threshold" and "Settled Piece Patience" tune how a neighbour's small drift wakes it.
• Fix Smoke Overhead (client) — writes each smoke puff's physics mass on 2% lifetime steps, rechecks its render chunk four times a second, and reads its position once per frame.
• Fix Unload Discovery Scan (both) — finds objects that left the loaded area through a per-zone instance index instead of walking every loaded object; "Object Unload Frame Budget" caps how many are handed to the engine per pass (default 250, 0 is vanilla).
• Fix Idle Wear Visits (both) — skips a building piece's whole wear visit while it is provably quiet: support asleep, locally owned, dry or roofed while wet, above the waterline, outside the Ashlands, and undamaged since the last visit.
• Fix Reflection Probe Spikes (client) — renders the realtime reflection cubemap one face per frame at a configurable resolution and reduced quality, holding a face back while the frame is over budget.
• Fix Physics Catchup Spiral (both) — caps how many fixed physics steps one frame may run to catch up after a stall (default 8; vanilla is about 16).
• Fix ZDO Value Write Allocation (both) — compares a ZDO field write against its stored value without boxing it.
• Fix Doubled ZDO Lookups (both) — reads ZDO data with one dictionary lookup instead of two.
• Fix Collision Contact Allocation (both) — reads a collision's contact points into a reused buffer instead of allocating an array per read.
• Fix Collision Callback Allocation (both) — turns on Unity's reuseCollisionCallbacks so one collision object serves every callback; the first suspect if a physics-touching mod that stores collision objects misbehaves.
• Fix Equipment Visual Refresh (client) — re-applies a character's skin and hair colour only when an input changed, and reads its equipment fields with one table lookup instead of thirty.
• Fix Light Settings Subscription (client) — registers lights for graphics-setting changes in a lookup table instead of a static event whose unsubscribe scans every other lit light.
• Fix Portal Idle Updates (client) — stops a portal re-writing its emission colour, light and audio every frame once the connection fade has finished.
• Fix Material Fader Settling (client) — stops a finished fade re-applying the same material property block to every renderer every frame; lingering corpses are the common case.
• Fix Cooking Slot Keys (both) — reads and writes a cooking station's slot data through precomputed key hashes instead of building six strings per access, as ArmorStand already does.
• Fix Station Range Scans (client) — answers the per-frame build-mode station and extension range queries with squared distances and one position read per candidate instead of two.
• Fix Smelter Catch-up Reads (both) — memoises a smelter's fuel and ore reads against its data revision, so an hour of missed production is not re-read once per simulated second.
• Fix Idle Sound Updates (client) — drops a finished one-shot sound out of the per-frame audio updater list until something plays it again.

Terrain

Fix Terrain Seams and Fix Terrain Paint Seams change only what is drawn, never what is saved, so they are client-only. Fix Terrain Paint Zone Fanout changes what is recorded, so it runs on every side.

• Fix Terrain Seams (client) — computes terrain lighting normals across zone boundaries, removing the hard crease along the 64 m grid.
• Fix Terrain Paint Seams (client) — merges the two copies of the paint on a zone boundary so dirt continues across the line instead of stopping dead; a lone stripe on the border is dropped.
• Fix Terrain Paint Zone Fanout (both) — records terrain paint into every zone it actually covers, including the neighbour about a metre west or south that vanilla left out; affects edits made from now on.
• Fix Terrain Paint Mask Indexing (client) — corrects the stride and bounds the optterrain console command uses to walk terrain paint data.
• Fix Terrain Compiler Init Race (both) — recovers a zone's terrain compiler that loaded before its heightmap existed, instead of throwing every frame and ignoring edits.

Correctness

• Fix Object Unload Crash (both) — recovers from an orphaned scene instance during object unloading instead of aborting the pass every frame.
• Tolerate Duplicate ZDOs On Load (server) — loads a save containing duplicate ZDO ids, keeping the later one and logging a warning, instead of refusing to load.
• Fix Effect Areas (both) — grows the fixed 128-collider buffer behind fire warmth and wetness checks when it fills, and removes destroyed characters from effect areas instead of throwing every physics step.
• Fix Fuel And Ore Loss (client) — takes ownership of a smelter, kiln or fireplace before adding fuel or ore, so the item cannot be lost to a dropped network message.
• Share Boss Defeat Keys (client) — gives every nearby player the per-player boss defeat key, not only the one whose client owned the boss; works against a vanilla server.
• Fix Recipe Amount Crash (client) — guards the null dereference that broke the crafting panel for a "requires any one of these" recipe with none of the ingredients carried.
• Fix Spawner Null Prefabs (both) — drops null entries from a spawner's creature table on load instead of letting one kill the spawner.
• Fix Projectile Rotation Spam (both) — stops the Look rotation viewing vector is zero log line that a projectile at zero velocity writes every physics step.
• Fix Send Failure Log Spam (both) — redirects the per-frame Failed to send data log line to debug logging.
• Fix Container Log Spam (both) — redirects the four log lines written on every chest open, stack-all and take-all to debug logging.
• Fix Item Icon Crash (client) — draws the first icon for an item whose stored icon variant is out of range instead of throwing from every UI panel.
• Fix Negative Stamina (client) — floors player stamina at zero (NaN included), repairs a character that loads in broken, and drops a UseStamina network message carrying NaN or infinity.
• Fix Dungeon Load Stall (both) — counts a dungeon room whose asset failed to load as finished and drops it, so the zone is not left flagged as loading forever.

The two log fixes redirect rather than delete: turn on EnableDebugMode and the messages come back.

Credit and sources

This mod fixes vanilla defects, and other modders found — and in several cases already fixed — a good number of them first. Where that is true it is recorded below, and in a comment at the top of the patch file.

The mods involved:

• ComfyMods — redseiko (GPL-3.0), the same licence as this project. Seven of its mods — BetterZeeLog, LetMePlay, BetterServerPortals, Scenic, Compress, Effectual and Atlas — account for eleven of the entries below.
• ValheimPerformanceOptimizations — ontrigger (MIT). Three of the performance entries below, including the event-fed spawn queue the object-stream rescan fix is built on, plus independent corroboration of two more.
• MyPitsDontLeak — Azumatt (MIT).
• Zen.ModLib — ZenDragon. Used as a reference; no code was used.
• Iron Gate Studio — Valheim itself. The decompiled game source is the reference used to locate defects; no game code is redistributed.

Performance

Fix	Sourced from	What came from there
Fix Portal Connection Scan	ComfyMods — BetterServerPortals	The indexing algorithm
Fix World Load Connection Scan	ComfyMods — Atlas	Its ConnectSpawners approach, extended here to portals and sync transforms
Fix Disconnect ZDO Sweep	MidnightsFX	—
Fix Tar Pit Buffer Disposal	MyPitsDontLeak — Azumatt	The root cause; our implementation is a transpiler rather than wholesale method replacement
Fix ZDO Packet Allocation	ComfyMods — Compress	The technique, taken on its own without that mod's GZip protocol change
Fix Mist Query Overhead	MidnightsFX	—
Fix Heightmap Lookup Scan	MidnightsFX	—
Fix Static Object Ground Checks	MidnightsFX	—
Fix Grass Rebuild Burst	MidnightsFX	—
Fix Terrain Builder Throughput	MidnightsFX	—
Fix Zone Collider Stall	MidnightsFX	—
Fix Prefab Query Scan	MidnightsFX	—
Fix Grass Ground Raycasts	MidnightsFX	—
Fix Background Zone Pacing	MidnightsFX	—
Fix Water Material Lookup	MidnightsFX	—
Fix Distant Terrain Hitch	MidnightsFX	—
Fix Idle Scene Sweep	MidnightsFX	—
Fix Support Lookup Cost	MidnightsFX; corroborated by ontrigger's ValheimPerformanceOptimizations (MIT)	Arrived at the same map-probe and lazy-default forms, and the single-fetch centre of mass
Fix Light Flicker Overhead	MidnightsFX	— (Point Light Limit exposes a dormant vanilla mechanism)
Fix Piece Event Stall	MidnightsFX	—
Fix Unload Sweep Cost	MidnightsFX	—
Fix Spawn Queue Churn	MidnightsFX	—
Fix Zone Occupancy Scan	MidnightsFX	—
Fix Piece Material Polling	MidnightsFX	—
Fix Idle Support Checks	MidnightsFX	—
Fix Smoke Overhead	MidnightsFX	—
Fix Unload Discovery Scan	MidnightsFX	—
Fix Idle Wear Visits	MidnightsFX	—
Fix Reflection Probe Spikes	ontrigger's ValheimPerformanceOptimizations (MIT)	Face-sliced probe rendering with quality clamps
Fix Physics Catchup Spiral	ontrigger's ValheimPerformanceOptimizations (MIT)	The maximumDeltaTime cap and its default
Fix Object Stream Rescan	ontrigger's ValheimPerformanceOptimizations (MIT)	Event-fed spawn queue, the zone-set diff, and the 8 m re-sort threshold
Fix ZDO Value Write Allocation	MidnightsFX	—
Fix Doubled ZDO Lookups	MidnightsFX	—
Fix Collision Contact Allocation	MidnightsFX	—
Fix Collision Callback Allocation	MidnightsFX	—
Fix Equipment Visual Refresh	MidnightsFX	—
Fix Light Settings Subscription	MidnightsFX	—
Fix Portal Idle Updates	MidnightsFX	—
Fix Material Fader Settling	MidnightsFX	—
Fix Cooking Slot Keys	Iron Gate Studio	The key-hash pattern, taken from ArmorStand.InitKeys
Fix Station Range Scans	MidnightsFX	—
Fix Smelter Catch-up Reads	MidnightsFX	—
Fix Idle Sound Updates	MidnightsFX	—

Terrain

Fix	Sourced from	What came from there
Fix Terrain Seams	MidnightsFX	—
Fix Terrain Paint Seams	MidnightsFX	—
Fix Terrain Paint Zone Fanout	MidnightsFX	—
Fix Terrain Paint Mask Indexing	MidnightsFX	—
Fix Terrain Compiler Init Race	MidnightsFX	—

Correctness

Fix	Sourced from	What came from there
Fix Object Unload Crash	ComfyMods — Scenic	The approach
Tolerate Duplicate ZDOs On Load	ComfyMods — Atlas	The duplicate-id tolerance
Fix Effect Areas	ComfyMods — Effectual	Both defects; our fix for the dangling reference differs
Fix Fuel And Ore Loss	Zen.ModLib (catalogue)	The root cause; rewritten as prefixes
Share Boss Defeat Keys	Zen.ModLib (catalogue)	The defect and approach; rewritten with one globally registered RPC
Fix Recipe Amount Crash	Zen.ModLib (catalogue)	The defect, rewritten
Fix Spawner Null Prefabs	ComfyMods — LetMePlay	The same fix
Require Lit Fire	Zen.ModLib (catalogue)	The defect, rewritten
Fix Run Attack Stamina Drain	Zen.ModLib (catalogue)	The defect; narrowed here to players only
Fix Projectile Rotation Spam	ComfyMods — BetterZeeLog	The same fix
Fix Send Failure Log Spam	ComfyMods — BetterZeeLog	The defect; that mod removes the call, this one redirects it
Fix Container Log Spam	ComfyMods — BetterZeeLog	The defect; that mod removes the calls, this one redirects them
Fix Item Icon Crash	ComfyMods — LetMePlay	The defect; a smaller fix here that leaves the shared item data alone
Fix Negative Stamina	MidnightsFX	—
Fix Dungeon Load Stall	MidnightsFX	—

Installation

Install with a mod manager, or drop ValheimCommunityPatch.dll into BepInEx/plugins.

Requires BepInEx and Jotunn.

Install it on the server and on every client to get all of it. It is not required on both: a modded client can join a vanilla server, and a modded server accepts vanilla clients. The mod adds no items, prefabs, recipes or save data, so a world it has touched still loads in vanilla, and the one network message it sends is ignored by anyone who does not have it.

What a one-sided install gets you:

• Server only — every (server) and (both) fix. The (client) fixes are not applied at all: a dedicated server has no local player, so nothing there could ever reach them. The startup log says exactly which counts you got.
• Client only — every (client) and (both) fix, for you specifically. The (server) fixes are installed but inert unless you are the one hosting.

Three caveats for mixed groups:

• Require Lit Fire and Fix Run Attack Stamina Drain are player-visible, so players with and without the mod will see slightly different behavior on the same server.
• Config values are only synced from the server to clients that have the mod — with a one-sided install each machine uses its own config file.
• Several fixes are applied by rewriting the method rather than wrapping it, and those read their config once when the game starts. Their descriptions say so. Changing one of those — including a value the server syncs down mid-session — does not take effect on that machine until it restarts.

If both the server and a client have the mod, their versions must match on major and minor; Jotunn refuses the connection otherwise, rather than letting the two sides disagree about behavior.

If a machine really does run headless but should still get the client fixes, set Patch Every Side in the config and restart. This is a last resort — it exists in case the graphics-device check that identifies a dedicated server ever gets it wrong.

Running alongside other mods

Several fixes here are applied by rewriting instructions inside a vanilla method rather than wrapping it, and other mods sometimes rewrite the same methods. All of this mod's rewrites are deliberately scheduled to run after everyone else's, and each one checks that it found what it expected and leaves the method alone if it did not. So where another mod has already fixed the same defect, that mod's version wins and this one stands down rather than fighting it.

When that happens you will see a line like "found no ZLog.Log calls to redirect, so this fix is inactive" in the log. That is the mechanism working, not a failure. A real failure looks different — fix(es) failed on the startup line, with the exception above it.

Known overlap: ComfyMods BetterZeeLog fixes three of the same defects (container request logging, "Failed to send data", and the projectile zero-velocity rotation warning). The two are safe to run together, and BetterZeeLog's versions of those three take effect.

Reporting a bug

Issues go to GitHub. Please include your LogOutput.log and the list of other mods you are running.

Contributing a fix

To decide whether a fix belongs here, the test is:

• Does it fix a defect in the game itself?
• Does it address a significant performance problem (eg 2-5x slowdown)

If it does not meet these criteria, it will not be accepted. This mod is purely bug and performance fixes.