---- Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 10/29/19 4:31 PM
Description: Initializing game

java.lang.BootstrapMethodError: java.lang.IllegalAccessError: tried to access class net.minecraft.client.particle.ParticleManager$IParticleMetaFactory from class its_meow.whisperwoods.client.init.ClientLifecycleHandler
at its_meow.whisperwoods.client.init.ClientLifecycleHandler.registerParticleFactory(ClientLifecycleHandler.java:36) ~[?:1.0.1] {}
at net.minecraftforge.eventbus.ASMEventHandler_42_ClientLifecycleHandler_registerParticleFactory_ParticleFactoryRegisterEvent.invoke(.dynamic) ~[?:?] {}
at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) ~[eventbus-1.0.0-service.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) ~[eventbus-1.0.0-service.jar:?] {}
at net.minecraftforge.fml.javafmlmod.FMLModContainer.acceptEvent(FMLModContainer.java:168) ~[?:28.1] {}
at net.minecraftforge.fml.ModLoader.lambda$postEvent$30(ModLoader.java:240) ~[?:?] {}
at net.minecraftforge.fml.ModLoader$$Lambda$2875/1613819889.accept(Unknown Source) ~[?:?] {}
at java.util.HashMap.forEach(HashMap.java:1280) ~[?:1.8.0_51] {}
at net.minecraftforge.fml.ModList.forEachModContainer(ModList.java:217) ~[?:?] {}
at net.minecraftforge.fml.ModLoader.postEvent(ModLoader.java:240) ~[?:?] {}
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:519) [?:?] {pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:365) [?:?] {pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.client.main.Main.main(SourceFile:155) [?:?] {}
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_51] {}
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_51] {}
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_51] {}
at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_51] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:56) [forge-1.14.4-28.1.10.jar:28.1] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider$$Lambda$352/2141066548.call(Unknown Source) [forge-1.14.4-28.1.10.jar:28.1] {}
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-3.2.0.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:50) [modlauncher-3.2.0.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:68) [modlauncher-3.2.0.jar:?] {}
at cpw.mods.modlauncher.Launcher.run(Launcher.java:80) [modlauncher-3.2.0.jar:?] {}
at cpw.mods.modlauncher.Launcher.main(Launcher.java:65) [modlauncher-3.2.0.jar:?] {}
Caused by: java.lang.IllegalAccessError: tried to access class net.minecraft.client.particle.ParticleManager$IParticleMetaFactory from class its_meow.whisperwoods.client.init.ClientLifecycleHandler
... 24 more

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Client thread
Stacktrace:
at its_meow.whisperwoods.client.init.ClientLifecycleHandler.registerParticleFactory(ClientLifecycleHandler.java:36)
at net.minecraftforge.eventbus.ASMEventHandler_42_ClientLifecycleHandler_registerParticleFactory_ParticleFactoryRegisterEvent.invoke(.dynamic)
at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80)
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258)
at net.minecraftforge.fml.javafmlmod.FMLModContainer.acceptEvent(FMLModContainer.java:168)
at net.minecraftforge.fml.ModLoader.lambda$postEvent$30(ModLoader.java:240)
at net.minecraftforge.fml.ModLoader$$Lambda$2875/1613819889.accept(Unknown Source)
at java.util.HashMap.forEach(HashMap.java:1280)
at net.minecraftforge.fml.ModList.forEachModContainer(ModList.java:217)
at net.minecraftforge.fml.ModLoader.postEvent(ModLoader.java:240)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:519)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:365)
at net.minecraft.client.main.Main.main(SourceFile:155)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:56)
at net.minecraftforge.fml.loading.FMLClientLaunchProvider$$Lambda$352/2141066548.call(Unknown Source)
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37)
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:50)
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:68)
at cpw.mods.modlauncher.Launcher.run(Launcher.java:80)
at cpw.mods.modlauncher.Launcher.main(Launcher.java:65)

Duplicate of #2

(Copied from #2)
Okay, using optifine preview versions 9 and higher should work! Just click the little preview versions button on the downloads page.

Okay actually I dunno what version you were using but I assume it's older than pre9, just updating to F$ (non preview!) should do what you want.