What is Time Machine and how do I back up my Mac with it?

Time Machine is Mac's built-in backup tool. Plug in an external hard drive, turn on Time Machine, and your Mac automatically saves copies of everything. If you delete a file or your Mac breaks, you can restore any version of any file from any day.

Time Machine is like a time-traveling copy of your entire Mac. It watches your files and saves new versions to an external hard drive every hour. When you accidentally delete something or your Mac has a problem, you go back in time and grab any version of any file from any day. It's the easiest, most automatic way to back up a Mac.