Reinstall Catalina

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The key to reinstall mac OS Big Sur, Catalina or Mojave without losing data is the backup, since no one can guarantee all data will be perfectly maintained after macOS reinstallation. However, if we unfortunately lost files after macOS reinstallation, Time Machine or Cisdem Data Recovery is helpful to recover them back. Here’s how to clean install macOS 10.15 Catalina on Mac via USB drive the right way using this guide. It’s been a long time coming, but macOS 10.15 Catalina is now available for anyone who has a compatible Mac. Here’s how to go about reinstalling macOS on your computer using Recovery mode and macOS Utilities. How Do I Reinstall macOS? Important: Should You Back Up Your. Reinstall operating system by using Internet Recovery mode. When you are sure that the Mac is able to access Internet Recovery mode, there is another important task before installing the fresh operating system version. After a successful reinstallation process, the computer will contain only the default software (which is delivered with macOS).

How to access and use the Internet Recovery mode on Mac computers?

Apple computers are well-known as stable devices with good performance and hardware specifications. The Mac operating system also includes various self-diagnosis and repair tools. Bear in mind, however, that these features might be susceptible to failure. When built-in tools or software-based solutions do not work, the last and most efficient solution is to reinstall the operating system. All modern Mac computers contain two separate methods to reinstall the operating system (by 'reinstall', we mean installation of a fresh OS X version). You can choose to install the operating system from a startup disk or via Internet Recovery.

In this article, we describe the second method: Internet Recovery to install the operating system version that came with the version of your computer. If your computer was released with OS X Mavericks, using Internet Recovery will install this particular version, while reinstallation from the recovery partition will result in a fresh version of the current operating system. Therefore, if you perform the reinstallation process via the Recovery utility, you will receive the same operating system version that existed prior to reinstallation. The Internet Recovery method is useful if you wish to downgrade the operating system. A big advantage of this method is the ability to bring back the computer to full functionality when software is corrupted. Note, however, that stable internet access is required to perform the reinstallation process via Internet Recovery. An unstable Internet connection can lead to the process crashing and no access to the computer. Therefore, you are advised to use an Ethernet network, rather than Wi-Fi. In this article, we walk through the entire Internet Recovery method.

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Requirements to access Internet Recovery Mode

Ensure that the Mac meets the minimum requirements to access Internet Recovery mode. All compatible computers are listed below. Bear in mind that some earlier versions of Apple devices might also use this feature. Apple state that Firmware updates grant access to Internet Recovery mode. If your device is older than the machines listed below, check the Apple firmware updates list here.

  • MacBook Pro (13-inch, Early 2011)
  • MacBook Pro (15-inch, Early 2011)
  • MacBook Pro (17-inch, Early 2011)
  • iMac (21.5-inch, Mid 2011)
  • iMac (27-inch, Mid 2011)
  • MacBook (13-inch, Mid 2010)
  • MacBook Pro (13-inch, Mid 2010)
  • Mac mini (Mid 2010)
  • MacBook Pro (15-inch and 17-inch, Mid 2010)
  • iMac (21.5-inch and 27-inch, Mid 2010)
  • MacBook Air (11-inch and 13-inch, Late 2010)

If you wish to reinstall the Mac operating system, your network must use DHCP and WPA/WPA security methods. All authentication methods listed below are incompatible with macOS installation via Internet Recovery. If your network uses one of the methods listed, change the setting to a compatible configuration (at least for the purpose of the installation process).

  • WEP
  • WPA-Enterprise
  • Certificate-based authentication / 802.1x
  • Proxies (where specific proxy servers must be configured in network preferences)
  • Captive Wi-Fi networks (where you click an “Agree” button to access the Internet)
  • PPPoE (where there is no router handling the PPPoE connection)

Reinstall operating system by using Internet Recovery mode

When you are sure that the Mac is able to access Internet Recovery mode, there is another important task before installing the fresh operating system version. After a successful reinstallation process, the computer will contain only the default software (which is delivered with macOS). All personal data and applications that you have manually applied to the hard disk will be erased. To protect your personal data, create a backup with Time Machine or similar software. Finally, when you are ready to reinstall the operating system, click the Apple logo in the menu bar at top of the screen and select Restart or Shut Down. Once the system starts booting and you hear the startup chime, hold down the combination of Command, Option (Alt), and R.

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Reinstall Catalina From Big Sur

Keep holding these keys until the animated globe appears with the message below stating 'Starting Internet Recovery' and 'This may take a while'. Note: If you are using a Mac laptop, use the built-in keyboard to access Internet Recovery Mode, since keystrokes might not register properly on external keyboards.

Reinstall Catalina Macbook Air

Next, select the Wi-Fi network. If you are not using an Ethernet network, click the drop-down menu and select the desired network. You must confirm access to a Wi-Fi network by entering the password. Then press Return on the keyboard or click the checkmark symbol on the screen to continue.

Reinstall Catalina Os

After successful authentication to achieve the network connection, the Mac will begin to download a recovery system image from Apple's servers. You will see a progress bar monitoring the status of the download. Depending on your internet connection, this process may take some time. Ensure that the computer is connected to the power adapter.

When the image is downloaded, the OS Utilities window will pop-up, giving access to the usual features, such as Restore from Time Machine Backup, Reinstall OS X, Get help online, and Disk Utility. From this point, the process will be similar to the reinstallation via recovery partition. Detailed information about how to install the macOS can be found in this article.