I had this with my macbook….Basically there’s a compatibility issue with some extensions, for things like printers, mobile phone programs etc etc that don’t work on El capitan and prevent it from booting..
The solution is not that simple I’m afraid….I’m not particularly IT literate either but managed to follow some instructions of an Apple forum and worked out how to use terminal to move some extensions that were causing the issues…it’s straightforward enough but if you’re not sure what you’re doing, I wouldn’t advise you do it.
The Solution was to:
Hi,
Actually that didn’t work – it’s only showing system files for the Recovery Partition, not the “Macintosh HD” one, because you have FileVault enabled and you need to unlock your volume first (step 3 below):
Boot into Recovery Mode (cmd+R)
From the central menu open Disk Utility.
Then select the “Macintosh HD” partition, then “Unlock” or “Mount”
Select the Get Help Online link from the meunbar to open Safari.
Navigate back to this thread.
Select all of the writing in bold below and press cmd+C to copy it to the clipboard:
cd “/Volumes/Macintosh HD” ; ls -1 Library/Extensions/ ; find Library/Application\ Support -iname *.kext ; find System/Library/Extensions -ctime +2d -depth 2
Then go to the Utilities menu, open Terminal and press cmd+V to paste the long command into it.
Select all the output from that and press cmd+C to copy it to the clipboard.
Select the Get Help Online link from the meunbar to open the Safari again.
Navigate back to this thread.
Paste the output you copied into your reply to this post
(then the original poster, wrote some code to fix it….I edited what he wrote based on what the above churned out….I could give it a go for you….but in no way, shape or form am I a programmer!)