How to reinstall macOS without losing your files

2 min read · 7 steps · Updated 2 October 2026

Short answer

Back up the Mac, then start it in macOS Recovery: on a Mac with Apple silicon, hold the power button until the startup options appear and click Options. On an Intel Mac, hold Command + R while it starts. Choose Reinstall macOS, click Continue and select Macintosh HD.

Reinstalling macOS replaces the system files and leaves your apps, documents and settings where they are. It is the step to try when a Mac will not start properly or keeps misbehaving after other fixes. It needs an internet connection, because the installer is downloaded from Apple.

Menu names are from recent versions of macOS, where the settings app is called System Settings.

Step by step

  1. Back up first

    A reinstall is designed to keep your data, but a backup protects you if something goes wrong on the way: how to back up a Mac with Time Machine.

  2. Start in macOS Recovery

    Shut the Mac down. Apple silicon: press and hold the power button until Loading startup options appears, click Options and then Continue. Intel: switch the Mac on and at once hold Command + R until the Apple logo appears.

  3. Sign in if asked

    Select a user whose password you know, click Next and enter the administrator password. Connect to Wi-Fi from the menu at the top right if the Mac is not online.

  4. Choose Reinstall macOS

    In the window with the utilities, select the entry to reinstall macOS and click Continue. Follow the instructions on the screen.

  5. Select the disk

    If the installer asks you to unlock the disk, enter your login password. If it offers Macintosh HD and Macintosh HD - Data, choose Macintosh HD.

  6. Let it finish

    Keep the Mac plugged in and awake. Do not close the lid. The screen may stay black or show a progress bar for a long time, and the Mac restarts several times.

  7. Log in

    After the installation the normal login window appears, with your account and files in place.

Good to know

Which version is installed: on Apple silicon, and with Command + R on Intel, the current version of the macOS that was installed last. On an Intel Mac, Option + Command + R installs the newest macOS the Mac supports, and Shift + Option + Command + R the version it came with or the closest one still available.

To give the Mac away, you do not reinstall like this. You erase it first: how to factory reset a Mac.

If the installer does not see any disk, the Mac may need service, Apple says.

Milder steps to try before a reinstall: how to start a Mac in safe mode and Mac stuck on the Apple logo or loading bar: 6 fixes to try.

In short: Back up, start in Recovery (power button or Command + R), Reinstall macOS, Continue, Macintosh HD, keep the Mac awake.

Sources
  • Apple Support: How to reinstall macOS

Rules and prices change. Check the official source before you act.