How to reinstall Mac OS?

by Gabriel E. Hall - -


Issue: How to reinstall Mac OS?

I am going to give my old Mac to my sister. However, I want to get rid of all information, programs, etc. from my device. Though, I want to reinstall Mac OS. How can I do it?

Solved Answer

Reinstall Mac OS is not as complicated and hard task as it might seem from the beginning. A new version of the operating system can be installed from the Mac App store, or this procedure can be performed manually. Even if you are not very good with technology, you will be still able to complete the guide given below.

The main reasons why users decide to reinstall macOS are:[1]

  • Selling or giving away the computer;
  • Mac runs slowly;
  • Computer is not working right or does not boot;
  • Downgrade[2] or upgrade OS.

Differently than Windows,[3] Mac OS rarely crash or become sluggish. Hence, OS reinstallation due to slow computer’s performance is a rare occasion. In most cases, this procedure is needed when people say goodbye to their laptops or desktop PCs.

However, in order to remove all your files, apps, Apple ID and other information, you have not only reinstall OS but clean the disk as well. If you need to save some of the data, do not forget to create backups before you begin.

How to reinstall Mac OS

Two methods to reinstall macOS

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You can reinstall Mac OS either manually or automatically. Of course, an automatic method is simpler and requires fewer skills. Meanwhile, manual requires having some knowledge and dedicating some time to this procedure. However, we will explain how to perform both of the methods correctly.

Method 1. Install OS from Mac App Store

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To recover needed system components, please, purchase the licensed version of Intego Intego recovery tool.

Follow these steps to install macOS High Sierra:

  1. Open App Store.
  2. Enter macOS High Sierra in the search box, or you can access the High Sierra website directly.
  3. Click Download button. “Install macOS High Sierra” file should be downloaded in the Applications folder and run automatically.
  4. Click Continue in Install macOS High Sierra window and follow the instructions on the screen.
    Install Mac OS High Sierra

Note. If you are asked to type admin name and password, you will have to click Add Helper option to continue.

Method 2. Install from macOS Recovery

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To recover needed system components, please, purchase the licensed version of Intego Intego recovery tool.

Reinstalling Mac OS from the Recovery allows installing different versions of the operating system. Hence, before you start following the instructions, you have to make sure which version you want to reinstall.

  1. Reboot the computer and hold down one of the following key combinations in order to reinstall your preferred macOS version:
    Command (⌘)-R > installs the latest version that was installed on your Mac;
    Option-Command-R > installs the latest version which is compatible with your device;
    Shift-Option-Command-R (Requires macOS Sierra 10.12.4 or later) > installs the original version of OS that came with your Mac or the closest still available version.
  2. Release the keys as soon as you see the Apple logo or a spinning globe.
  3. You will see macOS Utilities window. Click Reinstall macOS option (or Reinstall OS X).
    Reinstall macOS
  4. Click Continue and choose your disk. If you cannot see this option, you have to click Show All Disks option.
  5. Additionally, you might be asked to enter your Apple ID and password.
  6. Click Install button.
  7. Your Mac will be restarted as soon as the installation is completed.

Additional tip: Erase startup disk

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To recover needed system components, please, purchase the licensed version of Intego Intego recovery tool.

If you need to reinstall Mac OS in order to sell it, you should consider erasing or formatting the startup disk. This step is necessary to clean your data, Apple ID and similar details.

In some cases, macOS installer delivers a warning that OS cannot be installed on the computer or volume because startup disk is formatted incorrectly. Hence, taking the following steps is also needed:

  1. Open macOS Recovery window as explained above.
  2. Click on Disk Utility option and choose Continue.
    Run Disk Utility
  3. Choose your device or volume which is located in the sidebar.
  4. Fill the following fields:
    Name: Type the name of your disk
    Format: Choose Mac OS Extended (Journaled) or APFS
    Scheme (if available): Choose GUID Partition Map
    Erase Disk
  5. Click Erase button.
  6. Wait until the process is over and quit Disk Utility to return back to macOS Recovery window. Then choose Reinstall macOS option an follow the instructions above to install Mac OS.
    Reinstall macOS

Recover files and other system components automatically

To recover your files and other system components, you can use free guides by experts. However, if you feel that you are not experienced enough to implement the whole recovery process yourself, we recommend using recovery solutions listed below. We have tested each of these programs and their effectiveness for you, so all you need to do is to let these tools do all the work.

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recovery software Happiness
Compatible with Microsoft Windows Compatible with OS X
Do you have any trouble?
If you are having problems related to , you can reach our tech experts to ask them for help. The more details you provide, the better solution they will provide you.
- a patented specialized Windows repair program. It will diagnose your damaged PC. It will scan all System Files, DLLs and Registry Keys that have been damaged by security threats. - a patented specialized Mac OS X repair program. It will diagnose your damaged computer. It will scan all System Files and Registry Keys that have been damaged by security threats.
This patented repair process uses a database of 25 million components that can replace any damaged or missing file on user's computer.
To repair damaged system, you have to purchase the licensed version of malware removal tool.

Prevent websites, ISP, and other parties from tracking you

Private Internet Access is a VPN that can prevent your Internet Service Provider, the government, and third-parties from tracking your online and allow you to stay completely anonymous. The software provides dedicated servers for torrenting and streaming, ensuring optimal performance and not slowing you down. You can also bypass geo-restrictions and view such services as Netflix, BBC, Disney+, and other popular streaming services without limitations, regardless of where you are.

A VPN is also crucial when it comes to user privacy. Online trackers such as cookies can not only be used by social media platforms and other websites but also your Internet Service Provider and the government. Even if you apply the most secure settings via your web browser, you can still be tracked via apps that you are connected to the internet. Besides, privacy-focused browsers like Tor is are not an optimal choice due to diminished connection speed.

Therefore, to stay completely anonymous and prevent the ISP and the government from spying on you, you should employ Private Internet Access VPN. It will allow you to connect to the internet while being completely anonymous, prevent trackers, ads, as well as malicious content. Most importantly, you will prevent the illegal surveillance activities that NSA and other governmental institutions are performing behind your back.


Recover your lost files quickly

Unforeseen circumstances can happen at any time while using the computer: it can turn off due to a power cut, a Blue Screen of Death (BSoD) can occur, or random Windows updates can decide to reboot the machine when you went away for a few minutes. As a result, your schoolwork, important documents, and other data might be lost.

Additionally, you might also be attacked by malware that can corrupt your Windows or encrypt files with a robust encryption algorithm, and ask for a ransom in Bitcoin for the decryption tool. Cybercriminals might not deliver what they promised, however, so it is better to attempt alternative file recovery methods that could help you to retrieve at least some portion of the lost data.

Data recovery software is one of the options that could help you recover your files. Once you delete a file, it does not vanish into thin air – it remains on your system as long as no new data is written on top of it. Data Recovery Pro is recovery software that searchers for working copies of deleted files within your hard drive. By using the tool, you can prevent loss of valuable documents, school work, personal pictures, and other crucial files.

About the author

Gabriel E. Hall
Gabriel E. Hall - Passionate computer expert

Gabriel E. Hall is an expert troubleshooter who has been working in the information technology industry for years.

Contact Gabriel E. Hall
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