Format disk to install mac os x

Sometimes, depending on your Mac model, Mac App Store might not give you the full installer for download.


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In such cases, it is better to download the installer directly from Apple. Once you have created the USB drive by following our guide, use it to boot up your Mac. Related How to change video quality from camera app in iOS To boot from your USB drive, plug it in, reboot your Mac and press and hold the Option key before the display turns on. At the Startup screen, select your USB drive and press return.

Once the process completes and you are greeted with the macOS setup screen, remember to restore your back up data from Time Machine or from your cloud storage. By Imran Hussain. Share Tweet Submit.

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How to delete Siri audio recordings and history in iOS By doing this, you ensure that none of your personal data remains and the recipient is in receipt of a Mac with an operating system that is as fresh as when it first left the factory. I can not emphasise this strongly enough. Backup your data before proceeding.


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The instructions that I will give, in this tutorial, will have catastrophic consequences if you have data that you need to keep and do not backup first. I recommend taking a Time Machine backup and, separately, cloning your hard drive. This ensures that you have two separate backups, thereby halving the chances of data loss. More importantly, I am assuming that you have tested the integrity of your backup s. For OS X To access these, turn on your Mac and hold the Command and R keys, simultaneously, immediately after you hear the start-up chime.

Keep hold of them! Within around 10—15 seconds, you will be shown the OS X Utilities options. For Snow Leopard, or earlier, insert the appropriate DVD then press and hold the C key immediately after the start-up chime.

How to format a startup drive for a Mac

The computer will start up using the install media. Alternatively, press and hold the Option key sometimes marked ALT at start-up to select the volume containing the installer. If you have more than one partition, on the hard drive, you may wish to remove these and return the hard drive to a single partition, first.

Now click Apply.

Why to erase a disk

A dialogue box will pop up to confirm the actions you are taking. If you are happy with this, click Partition. In Disk Utility , of OS X Utilities , select the partition in the lefthand column that you created in the previous step. It should default to this option. If you want to be super security conscious, you can select the Security Options button. The trade-off is time; the more secure it is, the longer it will take. There are four security options, ranging from fastest and least secure to slowest and most secure. Tip: The more faster the erase, the less secure it is. There is a chance that data recovery software will be able to retrieve personal information.

For maximum security, use an erase that writes more than once. Bear in mind, this can take a long time to complete. From this you can select one of two options in order to restore the operating system:. The first option allows you to restore your machine to the latest Time Machine backup, if you have one. Tip: If you attempt to reinstall OS X onto an existing partition without first erasing it, OS X will reinstall the operating system files and your user files will remain intact.

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If you wish to remove your data, you must erase the hard drive first. If your Mac originally shipped with OS X Instead, a grey folder with a question mark will flash on the screen. You will see the same thing if your hard drive suffers a catastophic failure. It means that your Mac is unable to read any data from the hard drive.

How to clean install macOS

Either because there is no data to read, or the data that is there is corrupted. In this case, reboot your Mac and hold down Command and R immediately following the start-up chime. Your Mac will then try to connect to the internet so that it can download the OS X Utilities back to the hard drive. In the case of operating systems including and preceding OS X


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