When you download the mod, you typically get a "Core" file and a "Planets" file.
Issue with Galacticraft · Issue #324 · PG85/OpenTerrainGenerator File name- Galacticraft-Planets-Mod-1.12.2.jar
is more than a file—it is the culmination of years of modding expertise, delivering a near-professional space exploration experience inside a block-building game. It invites you to leave behind your dirt hut, construct a multistage rocket, and set foot on alien worlds where the sky is a different color and the gravity tries to kill you. When you download the mod, you typically get
Only use trusted sources like CurseForge or the official Galacticraft GitHub. Never use “universal” JARs from random forums. When you download the mod
You only installed the Planets JAR. Fix: Download GalacticraftCore-Mod-1.12.2.jar and place it in the mods folder.