My iMac is stuck while trying to select a Startup Disk after memory and data wipe, please help.

This is for my iMac 27-inch 5K Retina, (Late 2015)


In my situation, my iMac has been recently performing very slow. Apps took over a minute to launch, there were choppy animations when resizing open windows, spinny-wheel cursor encounters, and crashes every single time i try to update to from Monterey 12.6.6 to Monterey 12.6.7. I had already previously moved all the iMac's data to my MacBook so I was okay with wiping everything off it to get it into working order again. I had used the Disk Utility menu to clear off everything from the iMac, all my accounts, photos, and data, including the Macintosh HD Disk. After the deletion process everything looked good after. I had rechecked the Disk Utility and had seen my internal Disk's name has changed from "Macintosh HD" to "APPLE" with a bunch of numbers. I didn't think much so I went to reboot the computer to attempt to get to the home screen to check on everything. I exited Disk Utility and was greeted by a pop-up that prompted me to select a Startup Disk. Nothing showed up, just an infinite loading icon with an empty area below it. I restarted the computer while holding 'Command'+'R' and had a different screen show up. It was a globe symbol with a bar that asked for a WiFi connection and I had connected my iMac to the internet as prompted. It took me to a grey screen with a new pop-up saying "⚠️ Storage system verify or repair failed. (-69716)" I closed the pop-up and 2 new pop-ups came in. One was the macOS Update Assistant saying "Updating:" but was stuck at zero. and a new window below it asking once again to select a Startup Disk, to which of course there were no selections. I've conducted First-Aid checks on everything and it all came up with no problems, and now I'm lost from here on out. I don't know if i can get this computer to work again.


I had seen the option to use Target Disk Mode but I have not tried it yet, I'm saving it as a last resort. Is there anything else I could do to bring the computer back? I'm not looking for file recovery I just want to have it ready for future use again.


It has been almost 3 days since this problem started, I left the computer on for nights hopefully waiting for macOS Update Assistant to do anything but there was no avail. This is the first time I have ever submitted a question to the Apple Support Community. I hope someone on here knows how to help me.


Posted on Jul 1, 2023 1:35 AM

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Posted on Jul 1, 2023 2:28 AM

Hi there!


I’d recommend trying to reinstall macOS from Internet Recovery. Shut down your Mac, then startup into Internet Recovery Mode by immediately pressing and holding the Option-Command-R keys at startup. Once in macOS Internet Recovery, choose a Wi-Fi network from the Wi-Fi drop-down menu (top right). Next, choose Disk Utility, and click Continue. When erasing your Mac, select "View" > "Show All Devices" in Disk Utility and erase the main drive. Its name will end in "Media". Make sure this information matches:

Name: Macintosh HD

Format: APFS

Scheme: GUID


After erasing your startup disk, quit Disk Utility, and choose reinstall macOS.


Jack

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Question marked as Best reply

Jul 1, 2023 2:28 AM in response to JC8173

Hi there!


I’d recommend trying to reinstall macOS from Internet Recovery. Shut down your Mac, then startup into Internet Recovery Mode by immediately pressing and holding the Option-Command-R keys at startup. Once in macOS Internet Recovery, choose a Wi-Fi network from the Wi-Fi drop-down menu (top right). Next, choose Disk Utility, and click Continue. When erasing your Mac, select "View" > "Show All Devices" in Disk Utility and erase the main drive. Its name will end in "Media". Make sure this information matches:

Name: Macintosh HD

Format: APFS

Scheme: GUID


After erasing your startup disk, quit Disk Utility, and choose reinstall macOS.


Jack

Jul 1, 2023 1:46 AM in response to JC8173

Before the computer started giving you problems, did you make any bootable backups using programs such as Carbon Copy Cloner or SuperDuper!? If so, you might now be able to boot from one of those backups, by


  • Shutting down the Mac
  • Attaching the backup drive
  • Starting up the Mac with the Option (⌥) or Alt key to get into the Startup Manager
  • Choosing the external drive from the Startup Manager


Mac startup key combinations - Apple Support


Jul 1, 2023 2:02 AM in response to JC8173

JC8173 wrote:

This is for my iMac 27-inch 5K Retina, (Late 2015)
I restarted the computer while holding 'Command'+'R' and had a different screen show up. It was a globe symbol with a bar that asked for a WiFi connection and I had connected my iMac to the internet as prompted. It took me to a grey screen with a new pop-up saying "⚠️ Storage system verify or repair failed. (-69716)"


I'm not sure if that error indicates "just" a corrupted filesystem (one that could possibly be fixed with an erase from Recovery mode – an erase that would lose all data), or something more.


Sometimes it might be due to a problem developing with a Fusion Drive. One of the people who posted in this thread was able to get theirs working again (though others worried that the initial error might have been a sign that the hard disk part of the Fusion Drive was about to go the trip).

Storage system verify or repair failed 69… - Apple Community


My iMac is stuck while trying to select a Startup Disk after memory and data wipe, please help.

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