MacBook
how do you re install mountain lion on my MacBook
MacBook Pro 13″, macOS 10.15
Question marked as
In order to install Mountain Lion, your MacBook must be pre-Early 2015. If you have Catalina installed, then it will not run Mountain Lion.
Assuming it can run Mountain Lion, then you will need a copy of the Mountain Lion Installer DVD. You can purchase the installer ($19.99) at Buy OS X Mountain Lion - Apple Store, and you can Download OS X Mountain Lion Update v10.8.5 (Combo) should you need it.