This is probably going to be a very tricky issue to pin down, but I'll try and explain what happens;
I have been using this mod-pack for a while, from what I can tell it will run smoothly for me and most of my friends. However, a few of my friends state that the pack is crashing for them and that they will just flat out crash to desktop when randomly in their world, single/multiplayer regardless. Nothing seems to be able to accurately recreate it, except that it can happen about a few minutes to a few hours into a server / world.
I have tried updating all the mods in the pack to their latest stable versions (as far as I'm aware), and have even tried taking mods out 1 by 1 to try and see where the issue lies, but cannot seem to find any main leads. What does strike me as odd, is when I ask my friends for a crash log, they just tell me they have "logs" folders and are not provided with a "crash-reports" folder. There has only been one instance where a crash log was created and that was when I was directly hosting the server over LAN. From what they have told me, they are all running the latest 64-bit Java 8 (171), and have at least 4GB or so of RAM allocated.
If the other log files would be of any use, e.g. "2018-04-11-1.log" I will provide them, as well as any other details I've missed. What strikes me as odd is the lack of a crash-report being created, as in it's almost not the pack crashing, but something in Java messing up... or maybe that's my way of excusing bad pack-making.
Thank you in advance for your time.
---- Minecraft Crash Report -------- Minecraft Crash Report ----// My bad.
Time: 17/05/18 20:21Description: Unexpected error
java.util.ConcurrentModificationException at java.util.HashMap$HashIterator.nextNode(Unknown Source) at java.util.HashMap$EntryIterator.next(Unknown Source) at java.util.HashMap$EntryIterator.next(Unknown Source) at hats.client.core.TickHandlerClient.renderTick(TickHandlerClient.java:63) at cpw.mods.fml.common.eventhandler.ASMEventHandler_478_TickHandlerClient_renderTick_RenderTickEvent.invoke(.dynamic) at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54) at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:140) at cpw.mods.fml.common.FMLCommonHandler.onRenderTickStart(FMLCommonHandler.java:335) at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:999) at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:898) at net.minecraft.client.main.Main.main(SourceFile:148) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) at net.minecraft.launchwrapper.Launch.main(Launch.java:28)