Reinstall Operating System Mac

9 Janvier 2021

Reinstall Operating System Without Disk
Reinstall Original Operating System
Restore Removed Apps Windows 10 Refresh

Has your Mac computer been running into issues lately? It might be time to give it a fresh OS (operating system) installation. This process is actually straightforward and simple. Here's how to reinstall your Mac operating system(OS).

How to reinstall macOS while in Recovery mode Click Reinstall macOS. Click on the drive on which you wish to install macOS. Enter your Apple ID and password if you're asked to, though you might not be. Step 3 Click Reinstall macOS. Select the Macintosh HD icon. The Operating System will begin to install and the computer may reboot several times.

Warning: Make sure you do a full backup of your files before you reinstall your operating system.

How to Reinstall Mac OS Using Recovery Mode

Reinstall Mac Operating System From The Recovery Partition Turn on the Mac and immediately press and hold down both the Command key and the R key. Once you see the Apple logo appear in the middle of the screen you can release the Command and R keys. When the Mac has completed its startup, you should see a window similar this one.

Most users use the key combination Command (⌘) -R to start Mac in ' Recovery Mode '. In 'macOS Recovery' mode users have access to utility applications as well disk Utility, Port and to the module installation / reinstalling the macOS operating system. Few know I can use it two other key combinations for entering macOS Recovery. Depending on your device, you might see options like 'Restore From Time Machine Backup,' 'Reinstall macOS,' 'Get Help Online' and 'Disk Utility.' If you have an external drive and have been creating Time Machine Backups, you can select the restore from backup option.

Using the Recovery Mode is an easy way to reinstall your Mac OS. Follow the steps below to get a new version of your operating system:

Note: Your Mac needs to be connected to the internet to install or reinstall macOS.

Restart your Mac. You can do this by holding down the power button or by clicking the Apple logo by the top left corner of the screen and selecting Restart.
As your computer is restarting, hold down the Command + R keys. Keep holding them down until you see the Apple logo appear on your screen. When the Apple logo appears, release the command and R keys.
When you are in recovery mode, click Reinstall macOS and then click continue.
When the installer window pops up, click Continue. You will be shown the terms and conditions for installing the OS. Click Agree and then select your hard drive in the next window. Click Install to initiate the process.

How to Install macOS By Wiping Hard Drive First

If you wish to do a clean installation of yourMac operating system, you will need to wipe the internal hard drive first. You shoulddo this if you are selling your device or giving it to someone else touse.

Restart your Mac.
While your computer is restarting, press and holding the Command + R keys.
Click Disc Utility and then click continue.
Click View > Show All Devices.
Select your Mac's drive and then click Erase. This will be the highest option in the device tree.
Click Erase and fill in the name, format, and Scheme.
- Name: You can choose any name you want, but it's recommended to name the disk something generic.
- Format: You can choose either APFS (Apple File System) or macOS Extended (Journaled). The Disk Utility will show the compatible format by default. Most older computers will be Journaled, while most modern laptops that come with solid-state drives (SSD) are APFS-formatted.
- Scheme: Choose GUID Partition Map
Select Erase by the bottom right corner of the screen. This step will start the process of wiping your Mac's hard drive. This process will take a few hours, so make sure that your Mac is plugged in. When prompted, click Done.
Once your data is wiped, you can then start the reinstallation process. If you are in the functioning recovery partition when you booted, you will see the Reinstall macOS option. Click the button, and the process will start.

This step will take a little while. When theprocess is complete, your Mac will restart. You can then create a new account.Skip creating a new account if you are selling or giving away your device.Leave that step to the new owner.

Installing a fresh copy or reinstalling the operating of your Mac is an easy process, as long as you are connected to the internet and your computer is plugged into a power source.

If you are having a problem with a specific application, you can learn how to uninstall programs from your Mac here.

Updated on January 29, 2020

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Part 1. Things You Need to Know before Reinstalling Mac OS

Is your Mac device not operating properly after a macOS Sierra installation? Or maybe, you are in the middle of the installation process and some kind of issue appeared.

One of the best methods to fix these problems is to reinstall your macOS Sierra. Don't fret about losing a lot of data though because of reinstall Mac OS Sierra.

Reinstalling your macOS Sierra won't do anything to your files, user settings, apps, and other data. What happens is a fresh copy of the said operating system will be installed within your Mac device again.

But what if you want to clean up all your data on Mac? What if you want to factory reset your Mac for it to go back to its original settings? Well, what you should is to clean install macOS Sierra.
The said type of installation process results in the removal of everything in your device. All documents and files will be removed. A reinstallation, on the other hand, will not delete the said files.
If you know that you want to keep your data (as opposed to removing all of them), you should read this guide to learn how to do a reinstallation of the macOS Sierra.
But before you do the entire process, you have to do a few things to prepare your device for the installation of macOS Sierra.

Before You Begin: Back Up Your Data

Although reinstallation won't delete your data, it's still important to be sure of it. That's why you have to back your data up. In case an issue appears, you can restore the backup and still have the files most important to you.
One possible method you can use for a backup is to use the Time Machine of your macOS. This Time Machine enables your device to automatically create backups.
Another way to do it is through iCloud and DropBox. You can also utilize external hard drives to back your data up. Another thing you might want to do before the reinstallation of the macOS Sierra is to clean your device of junk, including clean the application cache.
You might also want to clean it of unwanted files like browser extensions and app leftovers. This might be a good thing to do since it results in a better installation of the operating system--no clutter will be around once you have the new macOS.
So, how do you wipe your Mac and reinstall? Well, you can do it manually or you can do it with a tool. We recommend that you use Mac cleaner tool for the process to be completed quickly. And the software we would recommend is the iMyMac's Mac Cleaner which can also help your Mac purgeable space be removed.
Below are the features and advantages of this cleaner:

1 - One-Click Feature - This means you can simply do a complete scan of your Mac in just one click. Nw20 mac powder. You can also clean your entire Mac device with a simple click.

Microsoft office for mac os x yosemite. 2 - Powerful - The powerful features of iMyMac's Mac Cleaner allows it to do a comprehensive scan of your entire Mac.

3 - Selective - It comprehensively scans your device and displays the results in a list. You can select the display method by a particular feature such as time and size, among others. You can preview each item and select the ones you want to delete if you want to. You are in control of everything.

4 - Free Trial - You are free to try the Mac Cleaner for the first 500MB of data. You will be able to experience its features without shelling out money from your pocket.

Here's how to use iMyMac's Mac Cleaner to clean up your Mac:

Step 1. Download and Launch iMyMac-Cleaner

Download the program from its official website. Launch the software on your Mac device. The main screen will display the system status of your device.

Step 2. Scan System Junk

Check out the left side of the screen. Select the module named 'Master Scan'. Press the Scan button to start the scanning process. Wait for a moment until all junk files are displayed to you.
The Mac Cleaner will display the junk files in various categories such as Application Cache, Photo Cache, Email Cache, System Logs, System Cache, etc.

Step 3. Review and Select Items to Clean Up

Select a category and preview the files in that category. Select the categories and specific files (in that category) you want to clean up. Press the button named Clean.

Step 4. Clean Up is Done

Wait until the selected files are cleaned up. These files will then be marked as Zero KB. Auto-recreated folders will not be marked as such.
Repeat steps 1 to 8. But this time on step 3, select the module 'Duplicate Finder' or 'Large & Old Files'.

Now, after you have your backup and after you have removed unnecessary clutter, it's high time to do the reinstallation.

Part 2. How to Reinstall macOS Sierra without Losing Data

Here's a step-by-step guide on how to reinstall the macOS Sierra on your device without losing data:

Select Restart from the menu.
Select Reinstall macOS from Utilities Window.
Choose a specific hard drive.
Wait for the entire process to be complete.

Step 1 - Select Restart from the Menu

Back your Mac up before starting the process (just a reminder). Look at the top-left corner of the window and press the Apple icon. From the menu, you will see, select Restart.

Step 2 - Select Reinstall macOS from Utilities Window

Then press the Command + R keys. A macOS Utilities Window will be displayed. Select Reinstall macOS and press Continue.

Step 3 - Choose a Specific Hard Drive

Choose a specific hard drive. Usually, this is the Macintosh HD.

Step 4 - Wait for the Entire Process to Be Complete

Press Install. Then wait for the entire process to be complete.

That's just about it. Easy. It's like taking candy from a baby.

Part 3. Conclusion

Having problems with the macOS Sierra? Or are there problems during the installation process? That's okay. We've got you covered.
You can reinstall the macOS Sierra to keep all your files and still have a fresh copy of the operating system. But before you do it, you should back up your files and clean your device using iMyMac's Mac Cleaner.
The tool is easy to use and it'll definitely prep up your device for macOS Sierra's reinstallation.

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Preparations you Need to Make Before You Reinstall macOS

To reinstall macOS on your computer smoothly. Follow the tips below to prepare your Mac ready for the new macOS update now:

Leave at least 2GB memory and 8.8 GB storage space on your Mac
Leave at least 45% battery on your Mac
Connect Mac to the internet or WiFi
Update your Mac Apps to the latest versions
Backup all your personal data and even create backups for your present Mac data through Time Machine

Remember to back up your Mac to an external hard drive for preventing system update failure or unexpected troubles from happening. Then follow the detailed guide below to reinstall Mac OS via macOS Recovery mode, which enables you to reinstall macOS, restore your files from Time Machine, repair or erase a disk, and more.

How to Update & Reinstall macOS Without Losing Data

*Print this page or open this page on another device so you can refer to it later.

Step 1. Start up your Mac from macOS Recovery

Turn on your Mac and immediately press and hold 'Command + R', 'Option + Command + R', or 'Shift + Option + Command + R'.
Release the keys when the Apple logo, a spinning globe, or a pop-up for a firmware password appears.

Step 2. Select 'Reinstall macOS' from the Utilities Window and click 'Continue'.

Reinstall Original Operating System

Step 3. Follow the onscreen instructions to select the hard drive you want to install the OS on and start the installation.

Restore Removed Apps Windows 10 Refresh

Step 4. Don't put your Mac to sleep mode or close its lid during the installation. It's normal to see your Mac restart several times or the screen is white while you reinstall the Mac OS. Just wait patiently for the process to finish.

If data loss occurred after you reinstalled macOS, you can follow the next part to recover your missing files.

Recover Lost Data After macOS Reinstallation

If you have backed up your Mac before the reinstallation, you can retrieve your data from Time Machine, an external hard drive, or somewhere else, depending on the way you used to make the backup. If you haven't created any backups for your Mac, then you'll need the professional Mac data recovery software tool - EaseUS Data Recovery Wizard, to perform data recovery. With the help of this tool, you can easily recover the data lost due to macOS reinstallation:

Step 1. Select the disk location (it can be an internal HDD/SSD or a removable storage device) where you lost data and files. Click the 'Scan' button.

Step 2. EaseUS Data Recovery Wizard for Mac will immediately scan your selected disk volume and display the scanning results on the left pane.

Step 3. In the scan results, select the file(s) and click the 'Recover Now' button to have them back.

There are lots of data recovery tools available. But EaseUS Data Recovery Wizard, one of the best Mac data recovery tools, is our pick. It fully supports all macOS systems including the newest Catalina, Mojave, High Sierra, Sierra, EI Capitan, Yosemite etc. It allows you to restore all lost data with simple clicks. Office files, music, videos, emails or other archives can all be restored on your own.

Workable Solutions	Step-by-step Troubleshooting
Phrase 1. Preparations	2GB+ memory and 9GB+ storage space left on Mac > 45% + battery > Connect to internet..Full steps
Phrase 2. Change a USB port	Start Mac from macOS Recovery > Select 'Reinstall macOS' > 'Continue'..Full steps
Phrase 3. Recover Lost Data	After macOS installation, run EaseUS Mac data recovery software > Scan and recover lost data..Full steps