You need to do a factory reset. Here are two helpful documents. Please check before in the release notes, which firmware (Universal Control) fits to your Mac OS. http://support.presonus.com/hc/en-us/articles/210046863-How-to-reset-your-mixer-to-Factory-defaults-Factory-Reset http://www.presonus.com/support/downloads/StudioLive-24.4.2