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new hard drive

I had to install new hard drive in 21" imac. How do I reinstall the operating system?

iMac Pro

Posted on Aug 25, 2020 9:38 AM

Reply
Question marked as Top-ranking reply

Posted on Aug 25, 2020 11:15 AM

If this is a Late-2011 or later model:


Internet/Network Recovery of El Capitan or Later on a Clean Disk


     If possible, back up your files before proceeding.


You will need a fast, working Internet connection, preferably, Ethernet. If you must use Wi-Fi, you will be asked to select your network and enter the network password. This procedure will install the current version of macOS that is compatible with your model.


  1. Restart the computer. Immediately, at or before the chime, hold down the (Command-Option-R) keys until a globe appears.
  2. The Utility Menu will appear in from 5-20 minutes. Be patient.
  3. Select Disk Utility and click on the Continue button.
  4. When Disk Utility loads select the target drive (out-dented entry w/type and size) from the side list.
  5. Click on the Erase button in Disk Utility's toolbar. A panel will drop down.
  6. Set the partition scheme to GUID.
  7. Set the Format type to APFS (SSDs, only if installing Mojave or Catalina ) or Mac OS Extended, (Journaled.)
  8. Provide a volume name, usually "Macintosh HD."
  9. Click on the Apply button, then click on the Done button when it activates.
  10. Quit Disk Utility and return to the Utility Menu.
  11. Select Install OS X and click on the Continue button.


3 replies
Question marked as Top-ranking reply

Aug 25, 2020 11:15 AM in response to arniefrommi

If this is a Late-2011 or later model:


Internet/Network Recovery of El Capitan or Later on a Clean Disk


     If possible, back up your files before proceeding.


You will need a fast, working Internet connection, preferably, Ethernet. If you must use Wi-Fi, you will be asked to select your network and enter the network password. This procedure will install the current version of macOS that is compatible with your model.


  1. Restart the computer. Immediately, at or before the chime, hold down the (Command-Option-R) keys until a globe appears.
  2. The Utility Menu will appear in from 5-20 minutes. Be patient.
  3. Select Disk Utility and click on the Continue button.
  4. When Disk Utility loads select the target drive (out-dented entry w/type and size) from the side list.
  5. Click on the Erase button in Disk Utility's toolbar. A panel will drop down.
  6. Set the partition scheme to GUID.
  7. Set the Format type to APFS (SSDs, only if installing Mojave or Catalina ) or Mac OS Extended, (Journaled.)
  8. Provide a volume name, usually "Macintosh HD."
  9. Click on the Apply button, then click on the Done button when it activates.
  10. Quit Disk Utility and return to the Utility Menu.
  11. Select Install OS X and click on the Continue button.


new hard drive

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