How To Reinstall Mac OS: A Comprehensive Guide

Sometimes, your Mac Operating System may start to work erratically. At times, the only way you might solve this issue is by performing a clean install of your Mac OS. Or, suppose you might be thinking of selling your old Mac device or passing it on another user. Whatever the cause behind the reinstallation of Mac OS, you need to be conscious that you have to wipe your Mac device first and then restore it to the factory settings. The reinstallation of Mac OS is not an easy task and requires that you know the exact process of doing so. If you are unaware about the reinstalling process want to know how to reinstall Mac OS, then you have just arrived at the right place.

Here in this article, we are going to provide some amazing hacks which can help you to reinstall your Mac Operating System at a short span of time. Hence, you are advised to go through the article in its entirety and apply the steps and procedure given below to reinstall Mac OS.

Amazing Tips and Tricks to Reinstall Mac OS

There are a few steps to perform for the reinstallation process of your Mac OS. We are going to discuss each of them in detail. Stick to the steps given below.

Step 1: Clean the System Junk from your Mac Device

Before going to reinstall any Operating System, first, you need to clean the system junk as well as the outdated cache files of the system. Because these are a possible source for software disputes. If you clean them, then you can find a considerable amount of storage space taken by the system junk previously. And the old caches can also conflict with the installation of your Mac Operating System. Hence, it is necessary to perform this step.  

You can perform this manually. It is easier than using any third-party application. To clean the junk files manually, you should follow the steps mentioned below.

1. Tap on the ‘Finder’ window and navigate to the Go menu.
2. Select ‘Go to Folder’ from the Go menu.
3. Type ‘~/Library/Caches.’ Hit Return from the keyboard launch the folder.
4. Check all the folder available on the current window and delete their contents. Here you need to make sure that you don’t delete the folders themselves.
5. After that, you have to follow the same steps above. Just replace ‘~/Library/Caches’ with ‘/Library/Caches.’

Step 2: Back up your Mac OS

After cleaning the junk files, you need to create a backup of your Mac device. If you do not perform this step, you will be unable to retrieve the essential system files of your device. You will also be unable to restore anything if something goes wrong. Here you need to get help from the ‘Time Machine’ application, which is an in-built software of Mac Operating System. To perform this, you need to follow the steps given below.

1. At first, invoke the Time Machine app.
2. Then, tap on the ‘Select Disk’ option.
3. Now, you have to choose the location where you want to store your files. Here you can also use an external hard drive.
4. Next, move the cursor to the left side of the display and tap on the ‘On’ button to turn on the Time Machine.
5. Look at the right side of the display. There you will see three lines that prompt ‘Next backup’, ‘Latest backup’, ‘Oldest backup’ under the storage device name.
6. Now, you need to wait at least for 5 minutes until the backup should be programmed.  
7. If you do not wish to wait, then you can navigate to the upper left side of the display and open the menu bar.
8. There you will see a few icons on the left side of ‘Date & Time.’ Tap on the ‘arrow clock’ icon. Then, choose the ‘Back Up Now’ from the list.

Step 3: Sign out all the Apps

The programs you have installed on your Mac Operating System is authorized to you. That means you can’t transfer them to another user (except the Operating System). To avoid the difficulties with the new user trying to download and install programs which are authorized to you, you need to make sure that you sign out from all the application of your Mac device. To Sign Out from some essential apps, you need to have a glance at the points given below.

Sign Out from iTunes:

To sign out from the iTunes application, you should follow the steps given below:

1. First, launch the iTunes app on your Mac device.
2. Look at the left pane of the display and tap on the Menu bar.
3. Go to the Account section.
4. Tap on the ‘Sign Out’ option.

Sign Out from iMessage:

To sign out from the iMessage application, you should follow the steps given below.

1. First, invoke the iMessages app on your Mac device.
2. Look at the upper left side of the display and go to the Menu bar.  
3. Now, you will see a drop-down menu. Choose the option ‘Preferences’ from the list.  
4. Choose your iMessage account.
5. Tap on the ‘Sign Out’ option.

Sign Out from iCloud:

To sign out from the iCloud application, you should follow the steps given below.

1. At first, you have to tap on the Apple logo from the upper left side of the display.
2. It will open a drop-down menu. Choose the option ‘System Preferences’ from the list.
3. Tap on iCloud.
4. Now, you need to uncheck the ‘Find My Mac’ box.
5. When it prompts to type the system password, enter the password in the specific field.
6. Tap on the ‘Sign Out’ option.
7. When the device prompts the message ‘Remove data from this Mac’, tap on it.  

Step 4: Reformat the Hard Disk

After signing out from all the applications on your Mac device, you need to remove everything from the hard drive by reformatting it. To perform this, you need to follow the steps given below.  

1. At first, you have to Restart the Mac device.
2. Then, you will see that the startup disc is waking up. Press the R and Command key both at the same time from the keyboard and hold them. Now, the device will boot into the Mac OS recovery mode.  
3. Now, you have to tap on the ‘Disk Utility’ option. Then, click on the Continue button.
4. Tap on the View and then choose the option ‘Show all Devices’ from the list.
5. Now, you have to choose the name of your Startup disk. Most of the time, it is probably named ‘Apple SSD.’
6. Tap on the Erase buttons by going to the upper left side of the Disk Utility window.
7. Then, type a name (like Macintosh HD) for the file that you wish to destroy.
8. If the Mac OS is utilizing HFS+, then you need to choose ‘Mac OS Extended (Journaled)’ by going to the list of format. Or if the Mac OS is utilizing APFS, then you have to choose ‘APFS’ from the format list. Tap on the option ‘Troubleshooting’ to get further details on which format to choose.
9. Now, you will see a list of Schemes that are available on the system. Choose the ‘GUID Partition Map’ from the list.
10. Tap on the Erase button.
11. When the process is complete, choose the ‘Quit Disk Utility’ option from the drop-down menu of Disk Utility. You will find this on the upper left side of the display.

Step 5: Reinstall a clean Mac operating system

After completing the reformatting process the system becomes ready to perform a clean install of its Operating System. Now, you should be in the utility window after reformatting the Mac. If not, then restart the system, and press the Command and R keys simultaneously from the keyboard until the Apple logo appears.

Things to Consider Before Performing the Installation Process:

Before going to follow the installation steps, you have to consider the points stated below.

1. At first, you need to make sure that you perform the reinstallation process under the recovery mode. Check it by holding the Command and R simultaneously. It will ensure that you can install the Mac Operating System without using the Apple ID.
2. After that, you have to confirm that the Mac device is connected with the network to check the software. Or, you will be prompted to connect to the internet while performing the installation process.
3. When the display prompts to enter the password, you need to enter the password that you use to unlock the Mac device. Here, you do not need to enter the Apple ID.

Steps to Perform the Installation Process:

Follow the steps given below to perform a clean install of your Mac device:

1. At first, you have to restart the Mac device.
2. Now, you will see that the startup disc is waking. Press the R and Command key simultaneously from the keyboard. Then, the Mac will start boot into the Mac OS Recovery mode.
3. Tap on the ‘Reinstall macOS’ option to reinstall the OS that came included with the Mac. Sometimes, you will see the ‘Reinstall OS X’ option.  
4. Tap on the Continue button.
5. Now, you have to choose the hard drive. Most of the time it is named by ‘Apple SSD.’  
6. Tap on the Install button to install the newest version of the Mac Operating System that is available. The Mac will restart after completing the installation process.

• Here you need to make sure that you do not exit from the lid of the MacBook. Don’t put the Mac to sleep mode while running the reinstallation process, even if it takes a few minutes more. Because, if the system goes to sleep mode, it will stop the reinstallation process to proceed further and you will have to start again from the beginning. While running the installation process, the screen of your Mac device will go blank and will show the Apple logo. Sometimes, it also shows a progress bar for a few minutes.

1. When the installation process completes, press the Q and Command keys simultaneously. Here you do not need to follow the on-screen setup guidance.
2. After that, tap on the Shut Down option to turn the device off.  

Now, the Mac device becomes ready for a fresh start.  

Additional Guide: How to Reinstall Mac OS from USB

You can also reinstall your Mac device using a USB drive. Here you will need three fundamental things:

• The Mac OS Installer. You can download it by visiting the Mac Store.
• A Startup drive to install Mac OS.

Before going to install the Mac OS using USB, you have to create a bootable disk by connecting a USB disk with your Mac device.

Create a Bootable USB Flash Drive:

To create the bootable USB flash drive, stick to the steps given below.

Step 1:

At first, you have to connect the Mac with the USB flash disk. It must need to have a minimum of 12 GB available free space. Then, go to the Application folder. Click twice on the Utility folder. Now, navigate to the option ‘Terminal.’

Step 2:

Next, run the commands in the current Terminal window:

1st: mavericks:

sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install\ OS\ X\ Mavericks.app

2nd: Yosemite:

sudo /Applications/Install\ OS\ X\Yosemite\app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install\ OS\ X\ Yosemite.app

3rd: El Capitan:

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app.

Step 3:

Tap on the Return button. Then, type the password of your administrator account and tap on the Return button. When the window prompts to confirm, type the Y key from the keyboard to confirm that you wish to delete the volume. Again tap on the Return button. Now, you will see that the bootable USB installer is formed. Exit from the Terminal window after finishing this process.

The Reinstallation Process of Mac Device from USB:

Now, to reinstall the Mac device using USB, perform the steps as follows:

1. First, connect the bootable USB disk and Restart the Mac by holding the Option key.
2. When restarting the device, you will see a few options. Select the option ‘USB Installer.’
3. Then, go to the option ‘Disk Utility.’
4. Navigate to the upper left side of the display and choose your Main Drive.
5. Now, look at the top of the screen and tap on the First Aid button. Then, click on the Erase button.
6. Then, in the middle of the window, you’ll have to click on the drop-down list of Formats. Choose the type ‘Mac OS X Extended’ from the list.
7. Tap on the Erase button. It will start to erase the main drive.  
8. After finishing this process, exit from the Disk Utility window. Then, choose the ‘Install Mac OS’ option from the list.
9. Now, choose the main drive. Then, install a new Operating System on it.

After that, you have to follow the on-screen guidance to complete the installation process and enjoy the new Operating System on your Mac device.

Final Recommendation

In the above article, we have discussed some of the easiest ways to solve your queries related to ‘how to reinstall mac OS.’ We hope if you implement the above steps in their respective order, it will definitely help you to ease up your pain. After successfully performing the above steps, if you still face any kind of trouble, then you need to connect with a tech expert. In addition, you can contact Macbook Repair for an easy solution.