I have been crashing sometimes while launching my world. Actually, its when connecting to the server we are playing on.

Sometimes it will crash 2-3 times, and then start working. I attached the crash log

crash-2021-02-17_18.47.03-client.txt
|quark |r2.4-292

java.lang.NullPointerException: Unexpected error
	at vazkii.quark.content.client.module.UsageTickerModule.lambda$clientTick$0(UsageTickerModule.java:74) ~[?:r2.4-292] {re:classloading}
	at java.util.ArrayList.forEach(ArrayList.java:1249) ~[?:1.8.0_74] {}
	at vazkii.quark.content.client.module.UsageTickerModule.clientTick(UsageTickerModule.java:74) ~[?:r2.4-292] {re:classloading}
	at net.minecraftforge.eventbus.ASMEventHandler_1543_UsageTickerModule_clientTick_ClientTickEvent.invoke(.dynamic) ~[?:?] {}
	at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85) ~[eventbus-3.0.5-service.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:297) ~[eventbus-3.0.5-service.jar:?] {}
	at net.minecraftforge.fml.hooks.BasicEventHooks.onPreClientTick(BasicEventHooks.java:105) ~[?:?] {re:classloading}
	at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1414) ~[?:?] 

Hello! Quark's moved to 1.18 now-- unfortunately, this means that (unless your bug is critical and/or game-breaking), we're closing support for issues filed for versions prior to it (e.g. Quark on 1.16).

If your issue still occurs on 1.18, or if your issue happens to be rather critical (e.g. consistently crashing the game with no other mods present), please leave another note or open a new issue. Thanks for your cooperation!

looks like a duplicate of this #2853

I have been getting this error as well with Forge 36.0.21, 36.0.39, and 36.0.40.

I would try 36.0.42 as that is the most current but Tetra currently hard crashes with it (unrelated errors) - lol.

Server fail 36.0.21 (does not generate crash report):
https://paste.gg/p/anonymous/fb1333ee465a4e129aa459d454b400d5

Client Crash Report 36.0.39
https://paste.gg/p/anonymous/6c6e9cfe9cb5476da12478c70096e9fc