DaemonUmbra

Please read the "Logs" section of my signature below and provide the appropriate log in the appropriate manner.

Try updating or removing Optifine

Delete your CodeChickenCore config file

Please read the "Logs" section of my signature below and provide the appropriate log in the appropriate manner.

The filenames of some of your mods suggests you are not getting them from official sources, please read my signature for more info on why this is a bad thing. Please read the "Logs" section of my signature below and provide the appropriate log in the appropriate manner.

The filenames of some of your mods suggests you are not getting them from official sources, please read my signature for more info on why this is a bad thing.

Hmm, apparently the DataSerializers registry was added to 1.12.2 2 months ago (April 11 2019). What version of Forge was this world created with?

Update Java

Do you have a gradle.properties file in the project or in your [User Home]/.gradle folder?

Where does JAVA_HOME point to?

If you get errors without mods installed maybe send that log, yeah?

Please do not hijack threads, if you have an issue please make your own.

Do you have multiple versions of Minecraft/Forge installed? If so, do those versions have their own game directories?

Where are you getting your mods?

1.8.9 is no longer supported on this forum due to its age. Please update to a modern version of Minecraft to receive support.

1.7.10 is no longer supported on this forum due to its age. Please update to a modern version for Minecraft to receive support.

Run the Forge jar from the command line/terminal, what does it say?

That log is from 1.12.2, check your versions

Please read the "Logs" section of my signature below and provide the appropriate log in the appropriate manner.

No... just delete the config file

The config is broken

Are you playing single player or on a server?

Please don't necro old threads. If you have an issue make your own thread please.

Try removing Optifine

Try deleting that jar file and having the Minecraft Launcher re-download it, it's possible it's corrupted.