As reliable as Macs are, adware — including malicious ads — are now twice as likely to infect them than Windows PCs.
Jan 05, 2021 How to Reinstall mac OS Without Losing Personal Data. Reinstalling macOS (sometimes also called a “factory reset”) is usually a rare event, and you shouldn’t have to worry about it too much. But there are specific issues, self-inflicted or not, that are much quicker resolved with a clean installation of the OS. If you succeed in downloading the OS installation, your next step is to create a bootable USB or DVD and then reinstall the OS on your computer. How to download older Mac OS X versions via the App Store. If you once had purchased an old version of Mac OS X from the App Store, open it and go to the Purchased tab.
It’s not just adware — overall malware detections in Macs have spiked by more than 200% from 2018 to 2019. In 2018, there were only 4.8 detections on average. In 2019, this jumped to 11 detections, whereas PCs only had an average of 5.8.
If your Mac has fallen victim to these malicious files, you might have to wipe its slate clean. Reinstalling its OS can help you keep malware-caused damage at a minimum.
Ready to learn how to reinstall Mac OS the safest, easiest way? Keep reading then, as that’s exactly what you’ll learn in this post!
Situations That Warrant Mac OS Reinstallation
Not all issues would require you to reinstall Mac OS, but if it keeps crashing, then it’s a good idea. The same goes if your gear now runs at a snail’s pace.
That said, if your problems are due to crashing apps, try to uninstall and reinstall them first. If you have a super slow Mac, delete apps and files that you no longer use, and make sure you empty your Trash after. It’s also a good idea to limit your start-up or login items, which will help free up your Mac’s start-up disk and RAM.
If none of these work, then it’s time to uninstall and reload Mac OS. Of course, if you’ve decided to sell your Apple computer, then it’s a must to reinstall its operating system.
Before You Reinstall Mac OS: Create a Back-Up First
While it’s pretty easy to reinstall macOS, something wrong can still happen that may lead to data loss. In fact, software issues were a top reason behind 65% of consumers suffering from data loss in 2018. This is why you should first back-up all the data in your Mac before tweaking your gear.
Besides, your Mac has a built-in back-up technology in the form of “Time Machine”. You only need to connect an external hard drive and delegate it as your Mac’s backup disk. Your Mac will then automatically create hourly backups in this external drive.
You can also have Time Machine create a back-up of all the previous months you’ve used your Mac. This is the back-up you want before you remove and reinstall macOS.
Reload Mac Os X
Reload Mac Os
If you don’t have an external hard drive, you can create iCloud backups. However, you can only use up to 5GB free of iCloud storage. If your files only amount to 50GB or less, consider upgrading to the $0.99/month iCloud plan.
How to Reinstall Mac OS With a Complete Hard Drive Wipe
Wiping your Mac’s hard drive clean and reinstalling its OS is much like giving it a factory reset. Most people go with this option if they’re selling their Mac or giving it to someone else. You can also do this if you have a malware-ridden Mac and you want the fastest way to get rid of all these malicious files.
Accessing Disc Utility
To wipe your Mac’s hard drive, you need to access macOS Utilities first. Do this by restarting your Mac, and as it boots up, press and hold down the Command + R keys. This should make the “macOS Utilities” window appear.
Select the “Disc Utility” option and then hit continue. Click the “View” option and choose “Show All Devices”. Highlight the name of your hard drive and click “Erase”.
The next window will ask you to provide a “Name”, “Format”, and “Scheme”. You can leave the entries as is since your Mac will automatically populate them. Click “Erase” to start the hours-long process of wiping your Mac’s drive.
Depending on how much data you have on your computer, this may take several hours. To avoid disrupting the process, keep your Mac plugged in.
Reinstalling the OS
After wiping your drive, your Mac should boot on its own. It should then display the functioning recovery partition window. Here, you can select the option to “Reinstall macOS”.
This may again take a few hours, so keep your computer plugged in. Once it’s done with the reinstallation, your Mac should boot up again. This time, you’ll get a window asking you to create your Apple ID or account.
Congratulations, you’ve successfully reinstalled macOS!
Steps to Reinstall Mac OS Using Recovery Mode
The first step on how to reinstall Mac OS in recovery mode is to once again access macOS Utilities. However, you can uninstall and reinstall Mac OS X without having to wipe your drive. Instead of running Disc Utility, you can select “Reinstall macOS” right off the bat.
Important Reminder: You Need Wi-Fi to Reinstall macOS
One reason behind the ease of reinstalling macOS is that your Mac will get a copy of it via the Internet. You don’t need to download it on your own, nor do you need to install the OS from a physical disc. However, as your Mac will access Apple’s servers, you need a stable connection to the Internet.
That said, it’s best to connect your Mac to your home Wi-Fi rather than your mobile data service. You may also want to pause downloads from other devices. This way, you can prevent delays in the reinstallation of your Mac OS.
Follow This Mac Hack Now
There you have it, the easiest, safest ways on how to reinstall Mac OS. Now that you know how the process works, it’s time to get to work and create those must-have back-ups ASAP. Once you have your files saved in another location, you can then start reinstalling macOS.
Ready for more geeky guides that’ll help you resolve common computer issues? Then be sure to check out the Tech section — we’ve got more how-tos waiting for you there!
Start up from macOS Recovery
Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
Apple silicon
Turn on your Mac and continue to press and hold the power button until you see the startup options window. Click the gear icon labelled Options, then click Continue.
Intel processor
Make sure your Mac is connected to the Internet. Then turn on your Mac and immediately press and hold Command (⌘)-R until you see an Apple logo or other image.
If you're asked to select a user you know the password for, select the user, click Next and enter their administrator password.
Reinstall macOS
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.
- If the installer can't see your disk or notifies you that it can't install macOS on your computer or volume, you may need to erase your disk first.
- If the installer offers you the choice between installing on Macintosh HD or Macintosh HD – Data, choose Macintosh HD.
- Allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac may restart and show a progress bar several times, and the screen may be empty for minutes at a time.
When the installation is complete, your Mac may restart to a setup assistant. If you're selling, trading in or giving away your Mac, press Command-Q to quit the assistant without completing setup. Then click Shut Down. When the new owner starts up the Mac, they can use their own information to complete the setup process.
Other macOS installation options
When you install macOS from Recovery, you get the current version of the most recently installed macOS, with some exceptions:
- On an Intel-based Mac: if you use Shift-Option-Command-R during startup, you'll be offered the macOS that came with your Mac, or the closest version that is still available. If you use Option-Command-R during startup, in most cases you'll be offered the latest macOS that is compatible with your Mac. Otherwise you'll be offered the macOS that came with your Mac, or the closest version that is still available.
- If the Mac logic board was just replaced, you may only be offered the latest macOS that is compatible with your Mac. If you've just erased your entire startup disk, you may only be offered the macOS that came with your Mac, or the closest version that is still available.
Skin for sylenth1 mac. You can also use these methods to install macOS, if the macOS is compatible with your Mac:
- Use the App Store to download and install the latest macOS.
- Use the App Store or a web browser to download and install an earlier macOS.
- Use a USB flash drive or other secondary volume to create a bootable installer.