The macOS has several builtin troubleshooting routines you can use to fix and repair problems. I think one of the most overlooked features is booting into Recovery Mode. Most people think starting up in Recovery Mode (Cmd ⌘ + “R”) is just used for reinstalling the macOS. While this may be a necessary troubleshooting step, there are other things you can do in Recovery Mode. This article describes how to boot into Recovery Mode and what troubleshooting things you can do in there.