For newbies: You need TWO components to use RsyncUI. (1) RsyncUI, as described here. That's actually the CLI (character line interface) background application. (2) RsyncOSX, which is the actual GUI (graphical user interface) with the unfortunate retro-name. The link to RsyncOSX is above in the RsyncUI overview. - - If you're NOT running macOS 14 Sonoma, the version of RsyncUI you want installed is v2.6.9. You can check in the Terminal using: "rsync --version". And yes, it's odd that this new version, ONLY for Sonoma, is v1.7.9. It has to do with upgrading to SwiftUI coding, apparently. 🙃