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Installing Catalina on iMac currently on Sierra

Can I install Catalina on my iMac (27-inch, Late 2013) over my current MacOS Sierra, v10.12.6? 


Do I have to update the firmware first?


Can I still boot and run off of an external drive containing my current MacOS Sierra, v10.12.6, after the Catalina upgrade on the internal drive? 

iMac Line (2012 and Later)

Posted on Jul 28, 2020 5:49 PM

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Question marked as Best answer

tom marchy Said:

"Installing Catalina on iMac currently on Sierra"

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To do so, install via the following:

  1. Backup your Mac.
  2. Upgrade to High Sierra
  3. Upgrade to Catalina


IMPORTANT: Back Up your Mac:

Create a Time Machine backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong with the upgrade.

Posted on Jul 28, 2020 10:52 PM

2 replies
Question marked as Helpful

Jul 28, 2020 6:14 PM in response to Tom Marcy

tom marchy Said:

"Installing Catalina on iMac currently on Sierra: Can I install Catalina on my iMac (27-inch, Late 2013) over my current MacOS Sierra, v10.12.6?  Do I have to update the firmware first? Can I still boot and run off of an external drive containing my current MacOS Sierra, v10.12.6, after the Catalina upgrade on the internal drive?"

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Yes. Your Mac is compatible with Catalina.


So, install via the following:

  1. Backup you Mac.
  2. Upgrade to High Sierra with a USB Bootable Installer
  3. Manually Upgrade to Catalina.

---


In Depth:

I. Back Up your Mac:

Create a Time Machine backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong with the upgrade.


II. Upgrade to High Sierra with a USB Bootable Installer

Create a USB Bootable Installer:

  1. Go Here: How to create a bootable installer for macOS - Apple Support.
  2. Choose: the code for a High Sierra USB Bootable Installer
  3. Install: High Sierra from the USB Bootable Installer


Once Installed:


II. manually upgrade to Catalina.

Go Here: How to upgrade to macOS Catalina - Apple Support

6 replies
Question marked as Helpful

Jul 28, 2020 6:14 PM in response to Tom Marcy

tom marchy Said:

"Installing Catalina on iMac currently on Sierra: Can I install Catalina on my iMac (27-inch, Late 2013) over my current MacOS Sierra, v10.12.6?  Do I have to update the firmware first? Can I still boot and run off of an external drive containing my current MacOS Sierra, v10.12.6, after the Catalina upgrade on the internal drive?"

-------


Yes. Your Mac is compatible with Catalina.


So, install via the following:

  1. Backup you Mac.
  2. Upgrade to High Sierra with a USB Bootable Installer
  3. Manually Upgrade to Catalina.

---


In Depth:

I. Back Up your Mac:

Create a Time Machine backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong with the upgrade.


II. Upgrade to High Sierra with a USB Bootable Installer

Create a USB Bootable Installer:

  1. Go Here: How to create a bootable installer for macOS - Apple Support.
  2. Choose: the code for a High Sierra USB Bootable Installer
  3. Install: High Sierra from the USB Bootable Installer


Once Installed:


II. manually upgrade to Catalina.

Go Here: How to upgrade to macOS Catalina - Apple Support

Question marked as Best answer

Jul 28, 2020 10:52 PM in response to TheLittles

tom marchy Said:

"Installing Catalina on iMac currently on Sierra"

-------


To do so, install via the following:

  1. Backup your Mac.
  2. Upgrade to High Sierra
  3. Upgrade to Catalina


IMPORTANT: Back Up your Mac:

Create a Time Machine backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong with the upgrade.

Jul 28, 2020 11:05 PM in response to Tom Marcy

You can absolutely boot up and run your current OS Sierra from an external drive as long as it is bootable. The best way would be to use CarbonCopyCloner or SuperDuper to create a clone on an external drive. That would also function as a backup if necessary as you could clone your OS back in case there is a problem.

Installing Catalina on iMac currently on Sierra

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