OS X El Capitan is the twelfth major release of OS X for Mac computers. It was released on September 30, 2015. Some users have reported an issue where Mac refuses to finish booting after updating to OS X EL Capitan. If your Mac will not start up, stalls on gray screen with an Apple logo, here is how you can troubleshoot:
Please perform the steps below until your problem is resolved:
- Press and hold the power button for a few seconds until your computer turn off, then release the power button. Wait a few seconds and then press the power button to turn on your computer.
- I previously wrote an article about how to fix Mac startup problems. Follow the tips in that article.
- Try starting up in Safe Mode. To do this, turn on your Mac, when you hear the start up sound, press and hold the Shift key until you see the Apple logo. If your Mac can start up, the problem may be that your computer do not have enough space. Did you see any low disk space warnings before this problem? Your Mac should have at least 9 GB of free space. This article explains how to free up space on your Mac.
- Reset NVRAM: To do that, turn off your Mac, then turn on, when you hear the start up sound, press and hold the Command-Option-P-R keys. Your computer will restart, when you hear the second startup sound release the keys.
This should solve your Mac not booting issue. However, you will need to follow the steps highlighted below to fix the problems.
Continue to fix the issue
- Open Terminal in /Applications/Utilities
- Enter “system_profiler SPExtensionsDataType > ~/Desktop/kextList.txt” without the quotes and hit return(this will take a while to run).
- There should now be a kextList.txt file on your desktop, open it and press both the “Apple(Command)” and “F” keys to bring up the find.
- In the find field insert “Obtained from: 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
- Browse your drive to /System/Library/Extensions and remove any of the unsigned kext files.
- Reboot and you should be all set.
User Submitted Tip
Thanks to Adam for submitting this tip. Many of us use our Mac and MacBooks for professional audio and video editing purposes. If you happen to use any of the AVID software on your machine,
this was the cause of three of our computers not shutting down after the El Capitain upgrade. After removing the first shutdown will require “sudo shutdown -r now” from the terminal or press and hold the power button.”
Hopefully, after trying out these instructions, you will be able to get your new OS X up and running again.