Is your Mac getting old and it’s time to part away with it but unable to do it? It’s understandable. It is difficult for anyone to part away with things that have been with you for long. Even if you are getting something better in exchange, it’s just too difficult. How about giving your Mac a little make-over? I mean to erase the hard drive and re-installing a new macOS. Sounds good, isn’t it? Read on to find out how to erase and reinstall macOS.
Before you begin, make sure you copy the files to an external hard drive or another computer. Having a backup of your files is always a good idea.
Boot your Mac from an Installer or Recovery Mode
Recovery Mode in Mac is a heap of beneficial tools and the best way to erase and start reinstalling from starch. To boot into the recovery partition, turn off your Mac and start it by holding Command + R keys.
If your Mac is older than 2010, then you may not be able to use Recovery Mode. For these machines, you have to hold Options key when starting your computer and choose recovery partition.
If these two methods don't seem to work, don’t worry, you still have a couple of options left. You can gain access to recovery minus partition by making use of Network Recovery; hold Command + R + Shift while starting your computer and it's going download the Recovery components. If this also doesn’t work, you can make a bootable USB-installer for macOS Sierra and start from it by pressing Options key while you turn on your machine.
Once you are in Recovery Mode by any means, you are now ready to erase your Mac securely.
Erase the Hard Drive
This step is optional. If you want your all your data in place and only reinstall the OS, you can skip this step. All your files and users will remain untouched only the OS will be over-written. It is highly recommended to backup your Mac before you proceed with reinstalling. This will save you from losing your data from any unexpected incidents.
For a clean installation, you have to erase your hard drive. You can safely erase a hard drive on your Mac in Recovery Mode as well.
Let’s get started: click ‘Disk Utility’ option. depending on how you entered recovery mode, you’ll see the Disk Utility Option right away else, you have to search for Disk Utility in the menu bar. First click Utilities tab, then Disk Utility.
Now, you will the list of disks available. Select the primary disk and click Erase. If it is a mechanical drive, a window pops-up. Select Security Options. You can avoid this step if your Mac has SSD. Solid State Drive will securely erase the files.
Now, to write the data on the entire drive, move the dial-up. You have to do this only once to safely erase it, but if you are fearful, you can erase it three or four times. Once you are satisfied you can click OK. And once again: If your Mac has SSD, you can skip this step. Just give a name to the drive and click Erase. This will the start over-writing process.
Erasing your drive will take at least half-an-hour to an hour if you have used the dial-up once. If it is 3 or 4 times, better leave it overnight to do its job.
Now that you have erased your hard drive securely, you can now reinstall the macOS. Click Reinstall macOS key if you have booted from the recovery partition to start the installation process.
If you have used USB installer, click Continue to move to the installer. You will be asked to select the drive to which the OS has to be installed. Select the one which you named in the previous step. macOS will now start installing.
This will take while. Once it is done you’ll be asked to create an account. You have all new Mac with you now. You can copy all the data back your new machine which you have backed up. If in case you haven’t, don’t worry, there are plenty of utilities available which does the data recovery job for you. Find a tool to retrieve data after reinstalling Mac and you’ll have your files back on the computer just like before.
Senior Editor, Content Analyst and a fan of exceptional customer service. John develops and publishes instructional and informational content regarding partition management, Windows hot-fixes, data management and computer troubleshooting.
As a tenured data recovery specialist, John shares exceptional insights and blog posts about data loss and data recovery across any storage device. With 8+ years’ experience in writing for Data Recovery for both Mac OS and Windows OS computers, he is an avid learner who always wants to polish and simplify the data recovery process. John passes his free time playing Chess and reading Science Fiction novels.