Forge Version: 35.1.13

Minecraft Version: 1.16.4

Logs: https://pastebin.com/wScgFqkX

Description:

Whenever I launch forge it stops loading in the Atlas Stitching. All my friends play with the exact same modpack on a server togheter, the only difference is that they play on Windows 10 and I'm on a Mac. 

Debug Log: https://pastebin.pl/view/94e94388

Just under 3 minutes, just timed it.

try to wait some more i had a potato pc and it sometimes took 10 minutes to do all the atlas stitching for a light modpack with only 80 mods

I'm using 6GB for Minecraft, CPU: 1.8GHz Intel Core i5, RAM: 8GB 1600MHz DDR3

 

I'm trying Saksham4106's solution right now.

I've let minecraft run since my last comment, but are you sure it's my CPU it's still stuck at 'Atlas Stitching: .../blocks.png' This can't be rigth can it?

It says: Java | 75% CPU | 1:42:00 CPU-Time | 42 Threads | 70433 Idle Wake-ups

Not sure what idle wake-ups means but it doesn't seem right.

Also I want to add that I was able to play a modpack in 1.12.2 with I think 78 mods, now in 1.16.4 I started removing mods (because I thought some mod was causing the issue) and when I started adding mods above 77 it started doing this glitch. All previous session were able to start just fine (without having to wait more than 2 hours).

The amount of mods shouldn't matter. It's the mods that you're adding.

Considering the cpu is at 75% its not dead.. but it's not pegging.. Kinda weird. 

You'd have to put together the mod pack and see if others can reproduce and figure out which mod it is thats misbehaving.

This is the modpack we made: https://we.tl/t-ENwKB2pard, (I removed optifine because I know it causes a lot of crashes and changes the log, but my friends are able to play the modpack with optifine fine, I myself do get the same bug with optifine installed).