Under Application Support delete the ‘Zwift’ folder.Select the drop down arrow for Application Support.Go to the Menu bar at the top of your screen and select the drop down option Go.Open the Downloads folder and delete the ‘Zwift’ folder.Open the Documents folder and delete the ‘Zwift’ folder.Select Applications from left side menu and delete the Zwift application.Re-Installing will clear away your old install and download the latest version of Zwift onto your Mac or PC. Once you have any and all files you’d like to save backed up, follow the instructions below to re-download and re-install Zwift. Did you follow the instructions/procedure that Shooj linked above? Fresh Install Procedure