2010 iMac not accepting anything except Lion install

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2010 iMac not accepting anything except Lion install

I have recently restored a 2010 27” iMac. After wiping the drive and successfully installing OSX Lion from a boot drive, I have checked everything on the iMac works and now want to install High Sierra.

After wiping the drive again, it seems that HS won’t install. I have a HS bootable USB created from Apple’s terminal script and the installer app. Everything goes smoothly; booting to the USB, using disk utility to wipe the drive, then selecting the SSD to install HS onto. The installer then proceeds to the install as normal, but halfway through the loading bar the iMac restarts and boots back into the recovery main page (from the USB drive). I get an error message saying ‘Your Mac restarted because of the problem’.

i have tried resetting PRAM, but the issue persists. I also tried to reinstall Lion, and that works fine.

My only idea is that it’s something to do with the bootable drive. To create the Lion drive, I used Disk Utility on another Mac to restore the drive using the InstallESD.dmg file dug out from the Install Lion.app. However, I don’t think this method works with High Sierra.

Any help?

Posted on Apr 4, 2025 07:13 AM

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Answer 1

Apr 4, 2025 07:43 AM in response to CharlieB777

(I find macOS code names an unnecessary complication in these discussions. One more thing to go look up.)

Okay, so OS X 10.7 works. macOS 10.13 doesn’t complete the install, presumably after you’ve erased the entire internal disk volume (selecting view all disks, if that Disk Utility control goes that far back as 10.13) as a direct upgrade requires OS X 10.8 or later; a direct upgrade doesn’t work as far back as 10.7.

If you have not erased the entire device before the install, selecting GUID partitioned GPT, HFS+ journaled case insensitive, try that, and re-install.

Also ensure the iMac date and time are correct.

Try to run diagnostics too, if they’ll even run this far back:

Use Apple Diagnostics to test your Mac - Apple Support

If Apple Diagnostics won’t work, here are links to Apple hardware tests (AHT) that are downloadable from Apple at Apple (these downloads are directly at Apple, and are not copies stored at or downloaded from anywhere else), and if the newer diagnostics don’t work, the older hardware tests downloadable might:

https://github.com/upekkha/AppleHardwareTest

You’ll need AHT for iMac11,3

I suspect you may need to do an intermediate OS X version due to some firmware update here, particularly if that iMac had never run a “less-old” version. Or the hardware is just flaky.

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Answer 2

CharlieB777 Author

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14 points

Apr 4, 2025 07:50 AM in response to MrHoffman

Thanks for the help - I’ll try diagnostics and I’ll try HFS+, previously I have tried using APFS and Journaled.

the other thing I tried when I had Lion active was to get the El Capitain installer onto the Mac desktop and run it. It seemed to work, restarting when it should, however after restart it went into an ‘Installing’ progress bar with the Apple logo, then restarted again to the same error message at 23%. It then did this indefinitely, restart looping at 23% install progress.

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Answer 3

CharlieB777 Author

Level 1

14 points

Apr 4, 2025 09:43 AM in response to CharlieB777

Managed to solve this one. I took the SSD out, then used another 2011 iMac with HS already running to install onto the SSD with an external mount. Put it back into the 2010 iMac and I now have the HS setup screen.

I expect it was a firmware issue as you said - if this hadn’t worked I was going to try installing Mountain Lion and then using the HS app to upgrade straight on the 2010 iMac.

thanks for the help anyway

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2010 iMac not accepting anything except Lion install

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