How To Erase Mac And Reinstall Os. A popup window appears with a few fields youll need to complete. Backup Files on Mac.
Quit out of the Disk Utility app and this time choose Reinstall OS X and Continue. Step 1Download and install unetbootin from here. Click the Apple symbol in the menu bar and select System Preferences on your Mac.
Select Disk Utility from the utilities window of macOS Recovery then click Continue.
Remember you need to be connected to WiFi as it will download a fresh version of macOS Catalina. Select Erase and then confirm your choice. Select the local drive and click the Erase. Click Reinstall macOS key if you have booted from the recovery partition to start the installation process.
