When you install MuLab on your computer, MuLab comes with a library full of sounds and effects. This is called the Factory Library.
When playing with the MuSynth, MuDrum, MUX, MuVerb etc and editing these factory presets, you will come up with nice new sounds and effects that you want to save.
When you edit such factory preset and save it using the "Save Preset" button at the top of the editor, the presets will be automatically saved in your User Library, and the factory preset is preserved.
Using "Save Preset As" you can choose any location on your system.
By default your user library folder is located at the User/Library sub-folder in your MuLab installation folder.
But you can set a specific folder on your system to be your MuLab User Library folder.
This is done by editing MuLab/User/Settings/PreferredFilesAndFolders.Txt and add/update the line starting with UserLibraryFolderPath so it points to the folder you want.
Similarly you can also overwrite the default factory library location by editing MuLab/User/Settings/PreferredFilesAndFolders.Txt and add/update the line starting with AppLibraryFolderPath so it points to the folder you want.
A preset pack is a folder with presets that comes apart from the MuLab package.
Using A Preset Pack
You can install a preset pack anywhere on your system and drag-drop the first preset onto a rack slot or MUX editor.
This will open that first preset. From then on use the previous/next preset buttons to step thru the other presets.
If you want a preset pack to permanently appear in the preset list (e.g. when clicking an empty rack slot) then make sure you put that preset pack within your user library folder. This way it will be included in the preset library list
Creating A Preset Pack
Best way to create a preset pack is to store all relevant presets in a folder.
If you want you can also use sub-folders within that preset pack folder for neat organization.
Then make a zip file of that preset pack folder and share it with other users.
Note that if your MUX preset pack is using samples or background pictures for its front panels, then make sure these sample and picture files are stored in a sub-folder within the preset pack folder.
This way MuLab will make sure the sample links are stored relatively and so when used on another system, the links can be restored without problem.
So best to do this first when making a pack folder. Then when saving the presets in the pack folder they'll use the relative links.
Preset File Cache
In order to speed up access to the library, MuLab stores a "MuxPatchFileCache.MuData" file in each library sub-folder.
When you add/remove/change preset files from outside MuLab e.g. using the OSX finder/Windows explorer, then best to delete the MuxPatchFileCache.MuData for the relevant sub-folder(s).
You can never do something wrong with deleting the MuxPatchFileCache.MuData files, MuLab will automatically regenerate them when not found, it will only take a bit of time, once.