Forge version: 43.2.0 (1.19.2) crash - java.util.ConcurrentModificationException: null

[Achie]

Can someone help me with this? I don't know what these means

Crash logs

Quote

java.util.ConcurrentModificationException: null
    at java.util.HashMap$HashIterator.nextNode(HashMap.java:1597) ~[?:?] {}
    at java.util.HashMap$EntryIterator.next(HashMap.java:1630) ~[?:?] {}
    at java.util.HashMap$EntryIterator.next(HashMap.java:1628) ~[?:?] {}
    at java.util.AbstractCollection.toArray(AbstractCollection.java:202) ~[?:?] {re:mixin}
    at com.google.common.collect.Iterables.toArray(Iterables.java:300) ~[guava-31.0.1-jre.jar%23115!/:?] {}
    at com.google.common.collect.ImmutableMap.copyOf(ImmutableMap.java:635) ~[guava-31.0.1-jre.jar%23115!/:?] {re:mixin}
    at com.google.common.collect.ImmutableMap.copyOf(ImmutableMap.java:620) ~[guava-31.0.1-jre.jar%23115!/:?] {re:mixin}
    at net.minecraft.client.renderer.chunk.RenderChunk.<init>(RenderChunk.java:33) ~[client-1.19.2-20220805.130853-srg.jar%23435!/:?] {re:classloading,xf:OptiFine:default}
    at net.minecraft.client.renderer.chunk.RenderRegionCache$ChunkInfo.m_200481_(RenderRegionCache.java:106) ~[client-1.19.2-20220805.130853-srg.jar%23435!/:?] {re:classloading,xf:OptiFine:default}
    at net.minecraft.client.renderer.chunk.RenderRegionCache.createRegion(RenderRegionCache.java:55) ~[client-1.19.2-20220805.130853-srg.jar%23435!/:?] {re:classloading,xf:OptiFine:default}
    at net.minecraft.client.renderer.chunk.ChunkRenderDispatcher$RenderChunk.makeChunkCacheOF(ChunkRenderDispatcher.java:1384) ~[client-1.19.2-20220805.130853-srg.jar%23435!/:?] {re:mixin,pl:accesstransformer:B,xf:OptiFine:default,re:classloading,pl:accesstransformer:B,xf:OptiFine:default,pl:mixin:APP:flywheel.mixins.json:instancemanage.RenderChunkAccessor,pl:mixin:APP:flywheel.mixins.json:instancemanage.RenderChunkMixin,pl:mixin:A}
    at net.minecraft.client.renderer.chunk.ChunkRenderDispatcher$RenderChunk$RebuildTask.m_234467_(ChunkRenderDispatcher.java:970) ~[client-1.19.2-20220805.130853-srg.jar%23435!/:?] {re:mixin,xf:OptiFine:default,re:classloading,xf:OptiFine:default,pl:mixin:APP:flywheel.mixins.json:instancemanage.ChunkRebuildHooksMixin,pl:mixin:A}
    at net.minecraft.client.renderer.chunk.ChunkRenderDispatcher$RenderChunk$RebuildTask.m_5869_(ChunkRenderDispatcher.java:908) ~[client-1.19.2-20220805.130853-srg.jar%23435!/:?] {re:mixin,xf:OptiFine:default,re:classloading,xf:OptiFine:default,pl:mixin:APP:flywheel.mixins.json:instancemanage.ChunkRebuildHooksMixin,pl:mixin:A}
    at net.minecraft.client.renderer.chunk.ChunkRenderDispatcher.lambda$runTask$0(ChunkRenderDispatcher.java:195) ~[client-1.19.2-20220805.130853-srg.jar%23435!/:?] {re:mixin,xf:OptiFine:default,re:classloading,xf:OptiFine:default,pl:mixin:A}
    at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768) ~[?:?] {}
    at java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1760) ~[?:?] {}
    at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373) ~[?:?] {}
    at java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182) ~[?:?] {}
    at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655) ~[?:?] {re:computing_frames}
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622) ~[?:?] {re:computing_frames}
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165) ~[?:?] {}

 

[warjort]

The error does not identify a problem mod.

Probably the only way you will find it is to experiment with removing mods until the problem goes away. (Backup your world before removing mods).

Start with optifine and any other "optimisation" mods you have.