Reinstalling macOS on your MacBook can help when your Mac behaves strangely, does not start properly or keeps faltering after a failed update. The good thing: reinstalling does not have to erase your files. This article explains the difference between reinstalling with and without erasing, how to do it via Recovery mode and when it does and does not help.
Blue Apple repairs MacBooks in Amsterdam. We see reinstalling solve many software problems, but it does not help with a hardware fault. Further down you read how to tell the difference.
Two ways
- Reinstall without erasing: macOS is replaced with a fresh copy, but your files, apps and settings stay. This is the first step for a system that misbehaves.
- Erase and reinstall: everything on the Mac goes and you start clean. You do this when selling, or when nothing else helps. See resetting your MacBook to factory settings.
Preparation
- Make a Time Machine backup. Something can go wrong even when reinstalling without erasing.
- Connect the charger.
- Make sure you have a good internet connection: Recovery mode downloads macOS.
- Know your password and your Apple Account.
How to reinstall without erasing
- Start up in Recovery mode. On a Mac with an Apple chip: shut the Mac down, hold the power button until you see the startup options and choose Options. On an Intel Mac: hold Command + R during startup.
- Choose a user and enter the password if asked.
- Choose Reinstall macOS and click Continue.
- Choose your startup disk (usually Macintosh HD) and follow the steps. The Mac downloads macOS and restarts a few times.
Leave it alone in the meantime. Depending on your internet it takes from half an hour to a few hours.
Which version is installed?
Via normal Recovery mode you usually get the version now on your Mac, or the newest it supports. On Intel Macs Option + Command + R lets you choose the newest compatible version and Shift + Option + Command + R the version the Mac shipped with. Also see installing an older macOS.
When does it help?
- After a failed or interrupted update.
- When Apple's apps no longer open or system messages keep coming back.
- When the Mac hangs at startup because of a software fault.
When does it not help?
- The drive does not appear in the list, or Disk Utility reports errors that cannot be repaired.
- The Mac shuts off, restarts by itself or gets hot, even in Recovery mode.
- The screen, keyboard, battery or charging does not work.
Then it is probably hardware. Read MacBook will not start up.
What do you see during installation?
The screen can be black for a while, the progress bar can stand still for a long time and the Mac restarts a few times. That is normal. Do not press the power button while a progress bar or Apple logo is visible. Only if nothing at all happens after a few hours is something wrong.
After reinstalling
Your files and apps are still there. Check that everything works, install the latest updates and see whether the original problem is gone. If it remains, it is probably in an app or setting of your account, or in the hardware.
What we do at Blue Apple in Amsterdam
If reinstalling fails, or the problem comes back, we test the drive, memory and logic board. If there is data on it you need, we first try to secure it. More on our pages about MacBook repair in Amsterdam and MacBook data recovery.
Frequently asked questions
Do I lose my files if I reinstall macOS?
Not if you choose to reinstall without erasing first. A backup is still sensible.
Do I have to reinstall my apps afterwards?
No, they stay.
Can it be done without internet?
With a bootable USB stick, yes. See making a bootable USB stick.
