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TripleCMac Author

Level 1

13 points

Need help with reinstalling MacOS Sierra - iMac

I have an l iMac (late 2015) (Intel) which originally came

installed with MacOS Sierra. I am trying to reinstall MacOS after accidently

erasing Macintosh HD. I've restarted iMac in internet recovery mode and able to

reach MacOS Utilities window. After this, i select disk utility. There is an

internal disk with title Apple HDD HTS5... In here Macintosh HD is missing and

hence I created Macintosh HD partition. I click on Erase and then entered

Macintosh HD as Name; Mac OS Journaled as the format. Based on this Macintosh

HD partition was created.

After creating partition, I go back to MacOS utilities and

select Reinstall MacOS. I select installation of MacOS Sierra on Macintosh HD.

However, after a few minutes, I get the following error - "An error occurred

while preparing the installation. Try running this application again". I

tried a few time repeating some of the above steps but wasn't successful.

Any guidance to resolve above issue would be great.

Earlier Mac models

Posted on Mar 26, 2023 3:44 AM

Top-ranking reply

G_xvyy

Level 1

22 points

Posted on Mar 26, 2023 5:42 AM

Hi there, I will highlight the steps for you to reinstall and if wanted to upgrade the operatin system since it is from 2015.

1 - Boot up your iMac and hold press "cmd+R" when the MacOS Starting Chime is heard.

2 - Once in MacOS Utilities, select Disk Utility.

3 - Under Internal , Select Macintosh HD.

4 - Press Erase and Select the format to "MacOS Extended Journaled" and press erase

5 - Check again if the Disk has been erased and formatted. If not go to Partition and format the whole disk to MacOS Extended Journaled.

6 - After confirming the disk has been erased and formatted, exit Disk Utility.

7 - Connect your Wifi at the top right connect.

8 - Find the option to reinstall MacOS Sierra

9 - Follow the instructions set by the installer.

---------------------------------------------------------------------------

How to install newer software for iMac/MacBooks 2015

( Only after you have downloaded MacOS Sierra )

Choose your MacOS of choice ( this is as far as your Mac can support )

Links below can be only opended on Mac.

Open and follow the installer.

--------------------------------------------------------------------

Alternative way

Open the App Store

Search either

Big Sur

Catalina

Mojave

High Sierra

Download

Open and follow the installer.

Reply to the message if you have any problems.

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Need help with reinstalling MacOS Sierra - iMac

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