MSoundFactory instruments may require samples and other resources, provided by the MSoundFactoryEssentials addon, to work properly.
Best way to install MSoundFactoryEssentials is MDownloader. Start it by clicking Menu and selecting Download and install products. Alternatively, you can download it manually and install using Menu / Install pack.
MSoundFactory instruments may require drum samples and other resources created for MDrummer. MDrummer may actually be hosted inside MSoundFactory. To make sure everything works well, it's recommended to install all MDrummer packs
Same as with the essentials addon, install the MDrummer Packs using MDownloader (preferred) or manually.