Hello! I've been having a problem where most mods for 1.12 forge just don't work (Like bibliocraft, optifine, betterbuilderswands, ironchest, etc.) but some smaller mods like, Just enough items and journey map, do, well at least allow me to reach the main menu.

Post the FML log (logs/fml-client-latest.org in your game directory).

Here you go.

fml-client-latest.log

The log doesn't show anything out of the ordinary. Is this the log with the mods which don't work?

 No, at least I think. should I run the game with the none working mods installed then post the log?

Here, ran the game with the mods this should show the problem.

fml-client-latest.log

Spoiler

 

UE    actuallyadditions{1.12-r111} [Actually Additions] (ActuallyAdditions-1.12-r111.jar) 
UE    betterbuilderswands{0.11.1} [Better Builder's Wands] (BetterBuildersWands-1.12-0.11.1.242+7e4f3aa.jar) 

UE    ironchest{1.12-7.0.27.813} [Iron Chest] (ironchest-1.12-7.0.27.813.jar) 

 

 

These 3 mods errored, try updating them.

How do I do that? just redownload them?

Didn't work and even when I take them off the game still crashes.

This is the log with those three off.

fml-client-latest.log

I've been out of it for a while but it appears that Forge has had some internal changes that breaks compatibility with older versions. I believe it happened with Forge 14.21.1, which is the version you seem to be running. In the case of Bibliocraft you're using 2.4.1 which was built using an older version of Forge so you need to update Bibliocraft to 2.4.2 (or newer if you're reading this from the future).

 

This would then be true for all mods, if you use Forge 14.21.1 or newer you need to make sure that the mods are also updated to this Forge version or they will crash the game.