Saving a Multi is like saving the entire state of the plug-in for future recall. A Multi stores all of the settings from the MIXER page, the Multi FX, the LIVE MODE and STACK MODE pages, all MIDI Learn assignments and Automation, as well as all of the settings (including any unsaved edits) for each of the eight Parts.

By saving a Default Multi, you can customize Omnisphere to load all of your preferred settings each time you open a new instance.