Q: El Capitan update won't boot

same to me... what was helping in my case

sudo rm -rf /System/Library/Extensions/EltimaAsync.kext

Hello J_S. Does one need to be in recovery mode to use that, or can I go straight to Utilities>Terminal and use the sudo to save myself a lot of pain when next I restart the machine?

I have the same problem. None of the fixes work and I don't have time machine

try to start captain in reovering mode ...if the system is started, go straight to utilities-konsole and use sudo rm -rf /System/Library/Extensions/EltimaAsync.kext  

you have to confirm this by your password .... if it's done, restart your machine

HOPE it's also helpfull to you...if not, have a look in this" System/Library/Extensions" directory, maybe you have 3party drivers witch disturb the startup

juergen

Thanks Jurgen. Will let you know how it goes!

I am a member of this private ****. Three days and counting. Here's what I've tried:

1) tried safe mode. FAIL

2) tried recovery mode. FAIL

3) tried online recovery mode. FAIL

4) made a bootable USB with El Capitan. FAIL

5) made a bootable USB with Yosemite. FAIL

6) backed up critical folders and files via DiskUtility- Thankfully accomplished.

7) Erased - tried -  via DiskUtility my Macbook air startup drive.

8) Failed to erase via DiskUtility the APPLE Disk Image with the bogus OS X El Capitan on it.

Bogus BS from Apple for releasing this junk with no warnings. And stupid me for clicking on upgrade.

I wish I could just wipe the Macbook air clean, and install a fresh system but I cannot even do that!  Like I have time for this BS. Thanks, Apple!

I've had an almost exact experience on my Mid-1012 Mac Pro.

But I have multiple HD's in it and the ability to boot off whatever system I have on the HD of choice.

So...When El Capitan would boot after initial install I tried everything with SApple Tech;s Help.

Nothing worked.

I could clean install and get it running, but as soon as I migrated data/files/progras, it would hang on restart.

I finally re-intialized the drive and reinstalled Yosemite and spent the next 4 days migrating data/files/programs back onto it.

It's running fine, and until there;s a few versions of El Capitan working I'm sticking with my stable 10.10.5 Yosemite booting off a Crucial SSD.

Here's another little "Apple Trap".

Update to El Capitan.

Run Photos.

It'll request to migrate your photo library.

IF it runs, it will import them.

When the entire OSX Crashes, and you try to re-run your Yosemite Photos, it'll say the photo file only works with a newer version, and YOUR YOSEMITE PHOTO LIBRARY CAN'T BE READ ANYMORE.

If you don't have a clean backup of your Yosemite Photos File saved, you could lose everything.

BACKUP CRITICAL FILES BEFORE UPDATING TO El CAPITAN and then make another backup somewhere else to be safe....BEFORE UPDATING OR RUNNING 10.10.11

Don't ask me how I know. I do keep multiple back-ups in my Mac Pro, fortunately.

Thanks, Doc. Not working for me. I have some kind of El Capitan OS X "Apple Disk Image" showing up in Disk Utility, and I cannot delete it. I think it's kind of maybe what is running this mess. How does one reinitialize a hard drive? And can I do that from Disk Utility. I really don't need anything saved on the drive, but rather the ability to install SOMETHING, ANYTHING that works in terms of Yosemite or El Capitan, on the machine. Until then...doorstop.

I turned on my Macbook Pro late 2011 on Tuesday and the machine would not boot.  I am now realizing that this is likely the same issue that is discussed in this thread.  After a week of dealing with the genius bar and apple phone support, I am in the current situation:

*Starting in recovery mode (CMD R) to reinstall the OS allows me to boot the machine - wiping the drive is not necessary.

*A subsequent restart gets me back to square 1 and the machine will not boot.

*Apple suggested that FileVault may be the issue - I have turned this off (takes about 5 hours to decrypt), but it does not solve the problem.

*Apple was shocked to hear that I was able to access my (previously encrypted hard drive) in target disk mode (hold T through start up).  They also thought that I would have to wipe my drive and re-install the OS to log back into my machine).

*All my data is still on my drive, and I am not able to shut down my machine without re-installing the OS upon start up.

*I will not shut down until an upgrade is released.

Does Apple know about this problem, and are they working it?  I've spoken to about 6 Apple techs in the past 5 days and none of them know of this issue.  They all suspected that FileVault was the root cause.

File Vault is not turned on on my MacBook Air and never has been. So Apple that is not the problem!!

how and when do you do this? When you restart?

Have checked but do not have this extension on my Macbook Air (EltimaAsync)

Also don't seem to have /Extensions/EltimaAsync.kext, sadly. The Extensions folder doesn't even seem to exist. Thanks anyway Jurgen. Fortunately managed to restart - I only get two successful restarts after every reinstallation, so from now on ....

I had the same issues on release day but was seemingly one of the lucky few who was able to use CMD+R and have gone back to Yosemite via backups.

Apple must be using this file vault response as standard, although it fails miserably when you read the forums and see many of those who have had this problem re manual reboot freeze up don't use file vault - myself included.

I'm no tech wiz so was just glad I was able to revert back.  This seems to me to have been a complete fail for many who otherwise always have confidence in the main in Apple and their annual OS updates.  It has dented my confidence in a major way, and I will not be trying the update again until Apple clearly indicate they have sorted this sorts of issues out. 

I did wonder if in some cases it was just older hardware having a struggle, laptops from 2010/2011 or even earlier maybe just can't do it... but then mine was purchased in March of this year and it died so maybe not.

Anyways, my view to anyone is to revert back if at all possible, or if you're sensibly reading forums first, then just don't even bother until such time as these major (rather than the oftentimes cosmetic) bugs are resolved.

Wasted hours trying the fixes on my 2012 Mac Pro.

Gave up, reformatted, reinstalled Yosemitie and spent hours rebuilding everything.

Will NOT waste anymore time, since I have a fully function/stable 10.10.5 system working just fine.

If and when there's a "fix", I may still hold off till the .2-.3 versions have been released and get good reviews.

I saw the new computers at my local Apple Store running El Capitan. But they were plain vanilla Systems with NONE running any non-bundled 3rd party programs.  

My Mac Pro will Boot ElCapitan as a clean install, but as soon as I migrate any settings/programs/data, it hangs on re-start.

Apple has all my logs and gave me a laundry list of suggestions to get it to work.

After all the past days and days of trying, I'm not wasting anymore time on this.