Intel Imac Boot Loop

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Level 1

5 points

Intel Imac Boot Loop

I am running a 21” 2015 Intel Based IMac. I have experienced the boot loop experienced by others previously and wondered if this problem has been resolved as the thread has been closed?

In my experience the only way to get the IMac working is to erase all files in disk utility and then re install Yosemite, then updating to Big Sur.

Whilst this works for a while, if l switch the IMac off, or try and start it from sleep mode, the IMac does not respond or goes back into boot loop. I have tried to switch on via Safe Mode using the Shift Key or pressing the power on button, but neither work.

Any suggestions on a work around or a solution to this issue?

iMac 21.5″, macOS 11.7

Posted on Jul 9, 2025 11:32 PM

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Answer 1

Jul 10, 2025 09:07 AM in response to Davenham38

Regarding reinstalling macOS, for the sake of expediency I suggest that you create a bootable macOS installer for Big Sur. You can eliminate the time it takes to download Yosemite from recovery and the upgrade process. It only takes a few minutes to create and when the installer is done you can just toss it in a drawer and have it handy for the next time you need it. A 32 GB flash drive is more than big enough to get the job done.

Apple's guidance for that is here: Create a bootable installer for macOS - Apple Support

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Answer 2

Ingo2711

Level 9

77,739 points

Jul 10, 2025 12:41 AM in response to Davenham38

Did you try to use the Internet Recovery, to install the latest compatible macOS right away?

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If you used Option-Command-R to start up from Internet Recovery, you might get the latest macOS that is compatible with your Mac.

...

copied from: How to reinstall macOS - Apple Support

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Answer 3

Davenham38 Author

Level 1

5 points

Jul 10, 2025 06:26 AM in response to Ingo2711

Hi, thanks for the response. Yes I used Internet Recovery to install Yosemite, and then Applestore to update to Big Sur. The problem occurs only when I close down the iMac or go into sleep mode. When I try to boot up or wake up from sleep mode, the iMac freezes or goes into the boot loop again.

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