Possible Fixes

Yes

Modpack Version

2.20

What happened?

When I first started the world I had no issue opening the pause menu and the game Auto-Saving when the menu is opened.
After I closed and opened the World again I can't open the pause menu without my game completely freezing.

What I tried:
Waiting for the game, didn't help
Just playing without opening any pause menu, still froze at some point
increasing RAM
restarting my PC
reinstalling the modpack

My Specs:
32gb, 16gb are allocated (16gb were not exceeded)
i7-11700k not overclocked (never reached 100% usage)
all Stored on an M.2 SSD

This is what the console displayed when it froze after opening a pause menu

[23:10:03] [Server thread/INFO] [minecraft/IntegratedServer]: Saving and pausing game... [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/minecraft:overworld [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/the_bumblezone:the_bumblezone [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/allthemodium:the_other [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/undergarden:undergarden [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/eternal_starlight:starlight [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/minecraft:the_end [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/minecraft:the_nether [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/mahoutsukai:reality_marble [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/twilightforest:twilight_forest [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/allthemodium:the_beyond [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/deeperdarker:otherside [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/allthemodium:mining [23:10:03] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'ServerLevel[test]'/ae2:spatial_storage

EDIT NEW TESTING:

I joined into one of the Worlds that keeps freezing and after that I went into the World files and deleted everything. And after deleting it saves everything like usual and I can enter the pause menus without freezing. After closing and openening the game the issue begins once again

latest.log

https://gist.github.com/xKolshii/49695e5f4e28c5fb8f50f13427da5e2e

Developer reports

No response

I am experiencing the same issue. It happens 100% of the time I open the pause menu, and once in a while if I'm idle (but hasn't happened while I've actively been playing yet).

The last few things I did before the issue started were set up a complete Cooking for Blockheads kitchen, set up a tiny XNet network to dry rotten meat into leather with a drying basin, and a little bit of exploring in the overworld and nether.

Edit: For me, it started on 2.18 (which is what I started my world on) and upgrading to 2.20 did not fix it.

Try on latest