Mod Version: 1.12.2-3.6.2.1

Forge Version: 1.12.2-14.23.5.2800

Link to client log:
The log file exceeded the free user data limit and I would have to split it into at least three files to upload it. I can do that if it's necessary but if just the crash log is sufficient that would be great.

Link to crash log: https://pastebin.com/GvmKenvr

Background info: I was using an older version of Dsurround and had to go the nether but it wouldn't load. I let the game sit on the loading screen for about an hour and a half, but the ambient nether music (that I believe is added in Dsourround) was playing. I was able to identify Dsurround as the problem, so I updated to the newest version of Dsurround to be met with crashes on phase six out of seven on game loading. I believe the game calls this phase 4 of mod initialization.

Did you just add the mod to a pack?
No, but I did update from an old version.

Did it just start crashing, or has it always crashed?
Just started.

Did you update any other mods in your pack and it started crashing? This includes Forge.
No

Is the modpack you are using available online somewhere? If the crash is due to mod interaction having the pack available makes things much easier. It is much harder to work these types of issues with a private kitchen sink pack containing 250 mods.
Homebrew modpack. I can add a modlist if necessary.

I added OreLib 3.6.0.1 and also deleted the old dsurround configs, as suggested on the curseforge page.

Did you install MixinBootstrap?

Did you install MixinBootstrap?

I attempted to but the Curseforge only had 1.14 and 1.16 versions. I had seen in another thread that supposedly the 1.16.3 versions work with 1.12.2, but that just caused me to crash immediately.

DS requires at least Mixin 0.8. MixinBoostrap 1.0.5 should be the one to use. Try adding this mod as well - it could be a mixin load ordering issue: https://www.curseforge.com/minecraft/mc-mods/mixin-0-7-0-8-compatibility. You will still need to have MixinBootstrap installed.

Try renaming the DS jar to have a z in front.

Just tried it both with and without MixinBootstrap installed, no difference to previous attempts.

Are all your mods up to date? Also did you rename the jar setting the prefix to z?

As far as I know, all of my mods are up to date. I did set the prefix to z. I will look through my mods for updates one by one and then get back to you.

Alright, so I checked everything and also decided to try a different version of DS to see if it would launch, so I downloaded 1.12.2-3.6.1.0, as it is the latest version to have Mixin library embedded. That version launched fine, but I still had my original problem of going to the nether. Is there any specific version of Mixin that is supposed to be compatible with 1.12.2? I tried version 1.0.2-5 (all of the ones on the Curseforge), and they all made my game crash on boot.