Reinstall Mac Os After Hard Drive Upgrade

  1. Mac No Drives To Reinstall
  2. Reinstall Mac Os X After Hard Drive Replacement

When to reinstall macOS?

  • Firmware issues — Mostly, a firmware issue related to macOS demands a reinstallation of the operating system. It can happen when macOS seems to malfunction and can’t complete the needed operations.
  • Startup issues — Apart from the firmware, there would be a problem with your Mac’s startup or bootstrap program as well. Mostly, the issue is resolved by visiting Mac recovery mode.
  • Corrupt OS — Ideally, your macOS can get corrupt or compromised due to different reasons. In order to fix it or run troubleshooting, you would need to reinstall the OS.
  • Malware attack — A virus or malware can also infect the core function of macOS and would demand a complete reinstallation of the tool.
  • Other issues — There could be numerous other issues with your Mac as well that would demand a reinstallation. For instance, if your system has been upgraded to a corrupt macOS version or the update was halted in between, then you need to reinstall OS X.

Preparations before reinstalling macOS

  • Mostly, it takes 30 minutes to 3 hours to reinstall macOS (the exact time would vary among different OS and system models). Therefore, your Mac should be charged enough to complete the installation.
  • During the reinstallation process, your Mac might be overheated or restart multiple times. It is recommended to not keep it in the direct sunlight or a hot place during the process.
  • Chances are that your existing data on Mac might be deleted after the reinstallation. Thus, you can consider taking its backup if you don’t want to lose it.
  • Disconnect all the attached units like USB drive, SD card, etc. from your Mac beforehand. Also, if you think your system has been infected by a malware, then consider formatting it as well.
  • Your system might download the needed patches and updates during the process. Keep your Mac connected to a stable internet connection for a seamless updating.

How to Reinstall Mac OS?

Step 1: Backup Files on Mac

1. Backup files Using Time Machine

  1. Simply connect a secure data storage to your Mac and launch Time Machine by visiting Menu > System Preferences > Time Machine.
  2. Here, click on the “Select Backup Disk” so that you can manually choose a location to save the backup content.
  3. As a pop-up screen would appear, just select the available drive and confirm your choice. If you want, you can choose to encrypt your data as well.
  4. To further customize things, you can visit its “Options” and even enable the automatic backup feature.
  5. As a pop-up screen would appear, just select the available drive and confirm your choice. If you want, you can choose to encrypt your data as well.

2. Backup files Using Cloud Storage

  1. Firstly, go to System Preferences and launch the iCloud app. If you are not logged-in, then enter your Apple account details to sign-in.
  2. The iCloud app has options to sync various data types. Simply enable the features (by checking it) and turn on the backup feature.
  3. There is an “Option” button adjacent to some data types (like Photos) that you can visit to customize your backup.
  4. You can go to the “Manage” section from here to view how much space is left on iCloud. Since only 5 GB of space is provided for a free (basic) account, you can also upgrade your account as well to get more space on iCloud.

3. Backup files Using External Hard Drive

Step 2: Boot Mac in the Recovery Mode

  1. Firstly, go to the main menu by clicking on the Apple icon and choose to restart your system.
  2. While the system is restarting, press the Command and R keys at the same time till your Mac enters the Recovery mode.
  3. When you get the Utilities window on the screen, just click on the “Reinstall macOS” option and continue the process.

Step 3: Erase the Mac Hard Disk

  1. When you get the macOS utilities window, click on the “Disk Utility” option instead of reinstalling it. You can also go to the “Utilities” menu to get this option.
  2. As the Disk Utilities window will open, you can just select the drive that you wish to erase from the left panel.
  3. On the right, you will get its detailed information with numerous other tools. Just click on the Erase icon and confirm your choice (by entering the firmware password).

Step 4: Reinstall Mac OS X without Losing Data

  1. A confirmation message will appear, informing you about the reinstallation details. Just click on the “Continue” button to proceed.
  2. Subsequently, you will be asked on which disk you wish to install macOS. Simply select the inbuilt disk on your Mac to start the process.
  3. That’s it! Your system will reinstall macOS on it by performing all the needed tasks. You can just sit back and wait for the process to be completed and make sure that you don’t turn off Mac in between.
  4. In the end, you can just choose to restore data from the Time Machine backup. You can get this option from the macOS Utilities or just launch the Time Machine application on your system as well.

Mac No Drives To Reinstall

Recover Erased Files after Reinstalling Mac OS

Reinstall Mac Os X After Hard Drive Replacement

Step 1: Select a Location

Step 2: Scan the Location

Step 3: Preview and Recover

What’s Wrong with Mac

Reinstall from macOS Recovery

1. Start up from macOS Recovery

Command (⌘)-R



2. Decide whether to erase (format) your disk

3. Install macOS

  • If the installer asks to unlock your disk, enter the password you use to log in to your Mac.
  • If the installer doesn’t see your disk, or it says that it can’t install on your computer or volume, you might need to erase your disk first.
  • If the installer is for a different version of macOS than you expected, learn about macOS Recovery exceptions.
  • If the installer offers you the choice between installing on Macintosh HD or Macintosh HD — Data, choose Macintosh HD.

macOS Recovery exceptions

  • If macOS Sierra 10.12.4 or later has never been installed on this Mac, Option-Command-R installs the macOS that came with your Mac, or the closest version still available. And Shift-Option-Command-R isn’t available.
  • If you erased your entire disk instead of just the startup volume on that disk, macOS Recovery might offer only the macOS that came with your Mac, or the closest version still available. You can upgrade to a later version afterward.
  • If your Mac has the Apple T2 Security Chip and you never installed a macOS update, Option-Command-R installs the latest macOS that was installed on your Mac.
  • If you just had your Mac logic board replaced during a repair, macOS Recovery might offer only the latest macOS that is compatible with your Mac.

Other ways to install macOS

  • You can also install macOS from the App Store or Software Update preferences. If you can’t install macOS Catalina, you might be able to install an earlier macOS, such as macOS Mojave, High Sierra, Sierra, El Capitan, or Yosemite.
  • Or create a bootable installer disk, then use that disk to install macOS on your Mac or another Mac.




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