DaemonUmbra

The only fix is waiting for 1.17 or asking Mojang to retroactively update old versions to use the fixed LWJGL

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.16 is not currently supported, use Java 8-15

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Forge doesn't delete mods. However, CurseForge modpacks do not include mods that are distributed through the Curse network, mods that are hosted by Curse are instead listed in a manifest that then needs to be processed by the Curse client to properly install the pack.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Really old Minecraft versions are no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Delete alexsmobs.toml from your config folder

Try removing Optifine

Please provide debug.log (more info on where it is and how to provide it in my signature below, just expand the spoiler)

If you're talking about a zip made by a backup mod... yes that's how they work, by copying your save into a zip file for more efficient storage

Is this running on a server hosting provider or hardware you had lying around?

Forge does not currently support Java 16

Please provide debug.log (more info on where it is and how to provide it in my signature below, just expand the spoiler)

Try removing Optifine

User was banned for piracy. Buy the game.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Please provide debug.log (more info on where it is and how to provide it in my signature below, just expand the spoiler)

This is a mapping difference, the documentation was written before we started using Mojang mappings by default. What was create in MCP is of in Mojang

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support. Omitting the version does not change the rules.

Please keep this forum in English This usually means your mods are mismatched between server and client

Do you know Java?

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

No it won't, that's not the issue they're having.

Reply split into its own thread. Delete forge-common.toml from your config folder