What is checked
- Java too new for the loader, already on the first launch of a modded instance.
- A mod that requires another Java (Cobblemon asking for 21), recognized even on Fabric.
- A configured memory that does not fit the machine.
- A map version different from the instance version.
No guessing
Java, memory and the content on disk are read from what actually exists on the machine, not from what the launcher remembers installing.
- Installs that never break: repeating an install never damages what is already there, it only completes what is missing.
- "Repair" and "Verify installation" really repair the instance and clear the "Failed" mark when they finish.
Loaders and versions
- Vanilla, Fabric, Quilt, Forge and NeoForge.
- Quilt instances accept Fabric mods; NeoForge 1.20.1 accepts Forge mods.
- Forge 1.13 to 1.16 install. Old game versions (1.7 to 1.8) open.