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iMac (circa 2007) stuck in a perpetual reboot after upgrading to El Capitan

Like the title says, my iMac is stuck in an never-ending reboot cycle. I cannot boot into Safe Mode, but the one thing I can do (thankfully) is get to the recovery menu.


From here, I can restore my computer to a 2-year old back up state sporting Snow Leopard and then proceed to install the El Capitan from there after updating a few things like the App Store.


The iMac will successfully install and run El Capitan with no issues, but once I shut down or restart the computer, it will get stuck in the reboot cycle.


I've done this process three times so I know the El Capitan is the root of the problem here since I wasn't having any of these problems with Yosemite and I can restart and shut down with the after-mentioned Snow Leopard back up.


I've also tried resetting the PRAM and SMC since a few sources thought that might solve the rebooting problem, but no dice there either.


Any other suggestions?

iMac, OS X El Capitan (10.11)

Posted on Oct 3, 2015 7:05 PM

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5 replies

Oct 25, 2015 2:56 AM in response to twysaske

I finally found the solution on another post : Reboot fail after installing El Capitan help!!


To be able to follow the differents steps descripted below, I made a bootable USB stick with the 10.11.1 Update (with the DiskMaker application). I booted my iMac on it, and I ran through the installation process. When it was finished, I could see the desktop and I was able to follow the differents steps...

(The only thing to avoid was to shutdown the computer...(because it would have re-launch the booting loop...)).

So here are the differents steps I followed... These are in relation with the "extensions" :


I copy-pasted the answer of GSfromNL :

"

From OWC and edited by me:

1) Open Terminal in /Applications/Utilities

2) Enter "system_profiler SPExtensionsDataType > ~/Desktop/kextList.txt" without the quotes and hit return (this will take a short while to run).

3) There should now be a kextList.txt file on your desktop, open it and press both the "Command" and "F" keys to bring up the find.

4) In the find field insert "Not Signed" Copy the destination to the .kext file to a list for use later. (Click next to cycle through all of them.) Example: /System/Library/Extensions/JMicronATA.kext

5) Browse your drive to /System/Library/Extensions and create a folder by the name Unsupported, move any of the unsigned kext files to the folder Unsupported. Delete the Kexts from their original location.

6) Browse in /Library/Extensions and create again a folder named Unsupported. Look if there are more unsupported Kext's and move them to the folder Unsupported. Delete the Kexts from their original location.

7) Beware that there may be Kext's that are "not signed" that you want to keep because you may need them for programs known and trusted by you, so do not move them to the unsupported folder(s). If you did, no worries, you can always put them back later if there are troubles.

8) Reboot and you should be all set.

"


Good luck !

iMac (circa 2007) stuck in a perpetual reboot after upgrading to El Capitan

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