But what if after I do all this to wipe my computer before I sell it, the computer now starts up with a Folder with a question mark?
I turn on the computer and now it only shows me a folder with a question mark. I have tried to reinstall the OS X Mountain Lion but there is no disk to select when it tells me to "select the disk where you want to install OS X."
I did read a couple articles about needing to create a partition but it wasn't clear on exactly what to do, so I held off.
MacBook Air 13″, macOS 10.15