Unable to perform clean MacOS install using multiple methods

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Level 1

4 points

Unable to perform clean MacOS install using multiple methods

I currently have a mid-2017 iMac 27” installed with Ventura 13.5.2. It previously had Windows 11 too via bootcamp but I had formatted that partition and got rid of it.

I am currently trying to format my iMac and perform a clean install of Ventura. I have successfully done this on my other macs via the recovery mode so I am familiar with the normal process. However, in this case I cannot enter recovery mode on the iMac. It boots straight to MacOS (even with wired keyboard). It just keeps restarting when I hold down cmd+R.

I have tried the following solutions but none have worked:

Reset the PR ram
Internet recovery mode - goes into a Windows 11 recovery mode and says it is damaged
Forcing startup to install original MacOS (nothing happens)
USB bootable MacOS (works on my other macs but the iMac won’t go into the startup manager when holding down the option key on startup).
Installed Ventura on another partition on the same HDD and tried to go into recovery mode after (no change).
Resetted the SMC
Boot in safe mode

Is there a way to reinstall the recovery partition and force my iMac to boot into it?

Other options I am thinking about but not sure if it will brick the iMac.

Install MacOS on another partition and format the old partition. Live without recovery mode.
Put iMac into targeted disk mode and format the drive. I have read that if I do this I cannot reinstall MacOS on it again.
Install MacOS on an external HDD and try to boot from that and format the internal drive and reinstall.

Posted on Sep 12, 2023 3:53 PM

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Answer 1

Top-ranking reply

Encryptor5000

Level 5

7,568 points

Sep 18, 2023 7:50 AM in response to JoshoMac

JoshoMac wrote:

Hi Encryptor5000,

Unfortunately holding down cmd+opt+R does not work for me. I get a Windows Recovery error which is most like leftover from bootcamp.

https://discussions.apple.com/content/attachment/a1485392-629a-4da9-a7c0-39b3b8a1c236

Before I go down the route of erasing all my data via Find my Mac, if I do it, will it load up the global recovery screen or would I be presented with the same screen again?

Good question. I haven't tested what gets erased myself on an Intel-based Mac, but I'd assume at least everything except the EFI partition. Maybe that too, but the reason I mention this is because the Windows error screen you're seeing is because of some remnants in the EFI partition. (Boot Camp Assistant cleans this up when you use it to uninstall Windows instead of Disk Utility.)

If the EFI partition survives without changes, you'll likely land on this screen again. If the EFI partition is destroyed, the Mac will revert to Internet Recovery (since there's nothing else to boot).

Try these steps to remove the Windows bootloader from the EFI partition on your Intel-based Mac:

EDIT: It looks like you might have a Fusion Drive based on your "diskutil list" output. I adjusted step 3 so that the EFI partition on your 2 TB HDD gets mounted instead of the SSD EFI partition. The Boot Camp remnants are located exclusively on the HDD.

Start up in macOS and log into an administrator account.
Open Terminal, located in Applications -> Utilities.
Run this command exactly as shown: sudo diskutil mount disk1s1
Enter your admin password when prompted (Terminal won't show any characters) and hit Enter (Return).
If successful, the EFI partition should now be mounted and available in the Finder.
In the Finder, go inside the EFI partition. There should be 3 folders: "APPLE", "Boot", and "Microsoft". Microsoft should have some subfolders and files inside; Boot should only have 5 or less files inside (probably just bootx64.efi or something similar).
If the above is correct, delete the Boot and Microsoft folders from the EFI partition.
Restart your Mac and attempt to start up from Internet Recovery again.
If successful, the Windows error screen shouldn't appear this time. Hopefully Internet Recovery works as expected instead!

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Answer 2

BDAqua

Level 10

245,183 points

Sep 13, 2023 2:08 AM in response to JoshoMac

Hopefully you used Bootcamp to remove the Bootcamp partition.

1. Start up from macOS Recovery

Option-⌘-R

Upgrade to the latest macOS compatible with your Mac.

APFS won't work for Sierra, Sierra needs MacOS Extended Journaled. High Sierra won't work for APFS on earlier Macs.

What has often worked for others is to use this Restore Method instead of CMD+r keys...

Option-⌘-R

Upgrade to the latest macOS compatible with your Mac.

2017 iMac failing to install Sierra in re… - Apple Community

Clean Install of High Sierra: Multiple Fa… - Apple Community

An Error Occurred While Preparing The Ins… - Apple Community

In Terminal...

Type "sudo bless -mount /Volumes/Startup_Disk_Name -setBoot" without the quotation marks into the Terminal window. The Bless command changes the startup disk. Replace "Startup_Disk_Name" with the correct name of the disk you want to boot from. If the name contains spaces, enclose the entire path in quotation marks. For example, if your startup disk is labeled "My Mac," type the following command: sudo bless -mount "/Volumes/My Mac" -setBoot.

https://www.techwalla.com/articles/how-to-change-the-mac-startup-disk-from-the-command-line

Change a remote computer’s startup disk using Terminal on Mac - Apple Support (SG)

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Answer 3

Sep 13, 2023 6:31 AM in response to JoshoMac

Hi JoshoMac,

This is indeed strange behaviour. That said, there might be a way to force your Mac to land in Internet Recovery. Try these steps.

IMPORTANT: Before trying these steps, first try holding down Option-Command-R during startup/reboot. If successful, you should see a spinning globe. If you see the Apple logo and your Mac boots regular macOS instead, continue with these steps.

WARNING: These steps erase all data from your Intel-based Mac and lock it with a PIN you set. To prevent data recovery, enable FileVault and wait for encryption to complete before completing these steps.

Open System Settings.
Select your name at the top of the left pane/list, then choose iCloud.
Under "Apps using iCloud", select Show All.
Make sure Find My Mac is enabled.
Open the Find My app.
In Find My, choose Devices, then select your Mac.
Right-click (or hold Control as you click on) your Mac in the list, then choose Erase This Device.
Follow the onscreen prompts to remotely erase your Mac. WRITE DOWN AND SAVE THE PIN YOU SET HERE.
If successful, your Mac should shortly reboot and erase itself. It should then land in Internet Recovery.
Unlock the Mac using the PIN you set. After that, it should let you access the Recovery utilities.

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Answer 4

Old Toad

Level 10

210,455 points

Sep 12, 2023 4:12 PM in response to JoshoMac

NOTE: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Recovery volume. This makes it act as a wired keyboard as will insure a successful boot into the Recovery volume.

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Answer 5

JoshoMac Author

Level 1

4 points

Sep 18, 2023 4:08 AM in response to BDAqua

Thanks for the help. I have Ventura installed. Not sure if that makes a difference.

I tried the global restore by holding down cmd+opt+R but I get an error for Windows 10 recovery error (I guess is residual from when I had bootcamp).

I have tried the terminal command exactly as you stated for both my internal HDD and the bootable USB created to install Ventura. In both cases after entering my password I get the error “Can’t determine mount point of “name of drive”. Could not extract mount point.”

I have accounted for the spaces in the name of drives with the use of quotation marks as you have stated and no changes.

Lastly, when I type in Terminal the command “diskutil list”, I can see the recovery portion exists. I’m wondering if there is a way to force macOS to boot to it?

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Answer 6

JoshoMac Author

Level 1

4 points

Sep 18, 2023 4:12 AM in response to Encryptor5000

Hi Encryptor5000,

Unfortunately holding down cmd+opt+R does not work for me. I get a Windows Recovery error which is most like leftover from bootcamp.

Before I go down the route of erasing all my data via Find my Mac, if I do it, will it load up the global recovery screen or would I be presented with the same screen again?

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Answer 7

JoshoMac Author

Level 1

4 points

Sep 12, 2023 5:00 PM in response to Old Toad

Hi Old Toad,

I’ve plugging in my apple wireless keyboard into the iMac’s USB port and I get no change.

I know the keyboard is working (in the wired mode) because the mac reacts to reseting the PR ram and the internet recovery.

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Answer 8

JoshoMac Author

Level 1

4 points

Sep 24, 2023 8:14 PM in response to Encryptor5000

Thanks for the help. This has done the trick!

Was not straight forward for me though. I was able to get to the normal recovery mode after deleting the two folders and then allowed me to format the HDD.

Unfortunately it would not allow me install Ventura as I kept getting an error saying it was damaged. I reset the PR ram, SMC reset, first aid on the drives, and tried to boot up in global recovery, and USB bootable installation but did not work.

What did work in the end and I am not sure why but I unplug the iMac overnight and during that time I format the USB drive again and did another reinstall of Ventura install files on it.

Plugged it into the iMac and booted it up (not holding any keys down). As expected, it went to recovery mode but this time I was able to perform the installation without any issues. So not sure if leaving it unplug or the USB helped here.

With my iMac behaving like this, is it a possibility that the HDD is on it’s last legs?

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