Most installation failures are easier to solve when you reduce the mod set and check compatibility from the bottom up. Start with the loader, then dependencies, then the main mod, and only then the rest of the pack.
Missing Moonlight Lib
If the loader reports Moonlight as missing or incompatible, install the required build for your Minecraft version and loader. Avoid keeping multiple conflicting versions in the same mods folder.
Wrong loader or game version
A Fabric JAR in a NeoForge instance, or a 1.20.1 file in a 1.21.1 instance, can fail before the title screen. Recheck every filename and loader label.
Source archive mistaken for a mod file
The GitHub 1.21.1 ZIP provided on this site is a source archive. Do not rename it to .jar or drop it into the mods folder. Use a compiled release for normal gameplay.
Related guides
Continue with the focused guides in the sidebar or return to the full Supplementaries Mod guide library.