Stuck in Recovery Loop on iMac16,2 After attempt to factory reset - Internal Drive Wipe

Question

Level 1

4 points

Stuck in Recovery Loop on iMac16,2 After attempt to factory reset - Internal Drive Wipe

I am trying to factory reset this iMac16,2. I successfully booted into Internet Recovery and used Disk Utility to completely erase the internal hard drive (formatted as Mac OS Extended Journaled / GUID Partition Map). The drive is now completely blank.

When I attempt to run the default recovery installer provided by the servers (macOS High Sierra), the installation proceeds normally until exactly 4 minutes remaining, where it consistently fails with the error message:

"Could not create a preboot volume for APFS install."

The iMac is now stuck in a permanent loop defaulting straight to the macOS Utilities screen on boot. Attempted to wipe the physical root drive entirely under Disk Utility's "Show All Devices" view to force a clean container layout, but the High Sierra installer still fails at the preboot stage. Tried creating a bootable macOS installation USB using a modern MacBook Pro. However, due to the modern OS version on the MacBook Pro, Apple's standard web installers and frameworks block the download/extraction process due to hardware incompatibility checks, preventing me from creating the external media cleanly. What other options do I have to get the High Sierra or other compatible version installed in my iMac16,2?

Posted on Jul 6, 2026 11:02 PM

Reply

Answer 1

Top-ranking reply

SpiderMac

Level 3

578 points

Jul 6, 2026 11:05 PM in response to dupline

The High Sierra installer fails due to the APFS conversion bug. You can bypass it completely by installing the latest OS natively supported by your iMac:

Shut down the iMac.
Turn it on and hold Option + Command + R to boot into the latest compatible Internet Recovery.
In Disk Utility, erase the internal root drive as APFS (GUID Partition Map).
Exit Disk Utility and run the macOS Monterey installer.

If you absolutely need High Sierra, you must manually force the drive into APFS before running the installer:

In your current Disk Utility screen, click the View menu and select Show All Devices.
Select the top-level physical drive and click Erase. If APFS isn't available, format it as Mac OS Extended (Journaled) first.
Once formatted, select the new volume, right-click it (or go to the Edit menu), and select Convert to APFS.
Quit Disk Utility and retry the High Sierra installation.

To download a compatible macOS installer on your newer MacBook Pro without triggering hardware restrictions, open Terminal on the modern Mac and run:

softwareupdate --fetch-full-installer --full-installer-version 12.7.6

This command downloads the full Monterey installer directly into your Applications folder, allowing you to create the bootable USB using the standard createinstallmedia command.

Reply

Answer 2

Jul 7, 2026 9:35 AM in response to dupline

It appears an iMac 16,2 identifier is for a 2015 model. When booting into Internet Recovery Mode the two options are either macOS 10.11 El Capitan (Command + Option + Shift + R) or macOS 12.x Monterey (Command + Option + R). If the last OS installed on the system was macOS 10.13 High Sierra, then that may be an option as well with Command + R, but only if it was the last OS installed. I know that the High Sierra online installer is broken and requires a work around to address a "server not found/responding" error which you don't seem to be getting which tells me you may have been accessing a local recovery mode from a High Sierra installation you erased.

If you are installing macOS 12.x Monterey, then the drive must be erased as GUID partition and APFS (top option). I think Big Sur and earlier installers will automatically convert the drive to APFS during the install, but the Monterey installer will not. I recall the installer copying all the files & then complaining about a failure instead of complaining about a configuration issue before the install proceeded. It is possible the Big Sur installer also had this limitation.....it has been a long time and it is also possible that Apple modified the earlier installers Catalina & Big Sur with this limitation as well.

A very likely possibility is that the internal Hard Drive is worn out or failing which would not be surprising for such an old system. You did neglect to mention why you are wiping & reinstalling macOS.....that reason may be the same reason you are having problems.

Do you have access to another working Mac model from 2007 to mid-2022? If so, then you can use that Mac to create a bootable macOS USB installer. Which version of macOS USB installer will depend on the exact model of the other Mac. The exact model of a Mac is shown by clicking the Apple menu and selecting "About this Mac".

Reply