Instances and the launcher

An instance

An instance is a folder that holds one game’s mods, resource packs, shaders, settings and worlds. Each instance plays one Minecraft version with one mod loader, or none.

Keeping each game in its own folder means a modpack’s mods never mix with another’s, and deleting one leaves the others as they are.

Its installation in the launcher

For every instance, Modsmith adds an installation to the official launcher: the entries you choose from before pressing Play. It points the launcher at the instance’s folder and at the right Minecraft version and mod loader, and uses the pack’s name and icon.

Modsmith changes only the installations it added. Your own stay as they are, unless you import one.

Minecraft and mod loaders

Minecraft versions and mod loaders are shared. Modsmith installs them where the official launcher keeps its own, in its game folder, so two instances on the same version share one copy.

Naming an instance

Commands take the instance’s name first, as in modsmith add survival sodium. When you have only one instance, you can leave its name out. Names are the folder’s name, and complete when you press Tab.

Where things go

What	Where
Instances	Your user data folder, under Modsmith/instances (modsmith/instances on Linux)
Settings	config.toml; modsmith config path prints where
Downloads	Your user cache folder, under Modsmith; safe to delete
Minecraft and mod loaders	The official launcher’s game folder
Launcher installations	The launcher’s launcher_profiles.json, one per instance

Change where new instances go with modsmith config set instances_dir <folder>. Set MODSMITH_HOME to keep settings, instances and downloads in one folder. See settings.