- Start up your computer in macOS Recovery: ...
- In the Recovery app window, select Reinstall for your macOS release, then click Continue.
- Follow the onscreen instructions.
- How do I put operating system back on Mac?
- How do I do a clean reinstall of OSX?
- Can I completely wipe my Mac?
- Does reinstalling Mac delete everything?
- How do I reinstall Mac OS from USB?
- How long does it take to reinstall OSX?
- What happens if I reinstall Mac OS?
- Will reinstalling macOS make it faster?
How do I put operating system back on Mac?
Select Reinstall macOS from the utilities window in macOS Recovery, then click Continue and follow the onscreen instructions. Follow these guidelines during installation: If the installer asks to unlock your disk, enter the password you use to log in to your Mac.
How do I do a clean reinstall of OSX?
Restart your Mac. Choose Apple menu > Shut Down, press and hold the power button until “Loading startup options” appears, select Options, click Continue, then follow the onscreen instructions. In the Recovery app window, select Reinstall for your macOS release, click Continue, then follow the onscreen instructions.
Can I completely wipe my Mac?
You can wipe your Mac computer — or, in other words, factory reset it — through the macOS Utilities menu. This is a good plan if your Mac is malfunctioning, or you're looking to sell it. Doing this will wipe all of your personal data and applications. It'll be like you just turned on your Mac for the first time.
Does reinstalling Mac delete everything?
Reinstalling Mac OSX by booting into the Rescue drive partition (hold Cmd-R at boot) and selecting “Reinstall Mac OS” does not delete anything. It overwrites all system files in-place, but retains all your files and most preferences.
How do I reinstall Mac OS from USB?
Insert the USB drive and power up the machine. Hold the Option key as you do so, then release the Option key when a dark screen appears displaying your bootable volumes. Select the volume for your bootable USB drive, then click the up arrow or press Return. Your Mac will then reboot.
How long does it take to reinstall OSX?
Typically, if you have a stock 5400 rpm drive, it takes about 30 - 45 minutes using a USB installer. If you are using the internet recovery route, it can take over an hour, depending on speed of internet etc. If you have a SSD using a USB installer, it typically takes 15 minutes or so.
What happens if I reinstall Mac OS?
It does exactly what it says it does–reinstalls macOS itself. It only touches operating system files that are there in a default configuration, so any preference files, documents and applications that are either changed or not there in the default installer are simply left alone.
Will reinstalling macOS make it faster?
You might need to remove some startup programs, run updates on your system, or clean out your storage drive to fix this issue. But if none of these fixes have an effect, reinstalling macOS can likely help speed up your system. This is especially the case if your Mac is approaching a decade of life.