I just updated to Sierra 10.12.4 My 2011 iMac starts to reboot with grey screen apple logo and progress bar fills in then system stops. Can't boot to safe mode

Possible Fixes for El Capitan and Later Installations

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.

Be sure to backup your files before proceeding if possible.

1. Resetting your Mac’s PRAM and NVRAM
2. Reset the System Management Controller (SMC)
3. Start the computer in Safe Mode, then restart normally. This is slower than a standard startup.
4. Repair the disk by booting the from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volumeentry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and returnto the Utility Menu. Restart the computer from the Apple Menu.
5. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button below Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
6. Install Combo Updater Download macOS Sierra 10.12.4 Combo Update and install.
7. Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Reinstall OS X then click on the Continue button.
8. Erase and Install OS X Restart the computer. Immediately after the chime hold down the CommandandRkeys until the Apple logo appears. When the Utility Menu appears:

1. Select Disk Utility from the Utility Menu and click on Continue button.
2. When Disk Utility loads select the drive (out-dented entry) from the Device list.
3. Click on the Erase icon in Disk Utility's toolbar. A panel will drop down.
4. Set the Format type to Mac OS Extended (Journaled.)
5. Click on the Apply button, then wait for the Done button to activate and click on it.
6. Quit Disk Utility and return to the Utility Menu.
7. Select Reinstall OS X and click on the Continuebutton.

Startup – Computer Stops or Delays

Startup - Gray, Blue or White screen at boot, w/spinner/progress bar

Startup - Gray Screen

Startup Issues - Resolve

Startup Issues - Resolve (2)

Startup Issues - Resolve (3)

If you live near an Apple Store, make a Genius Bar appointment to have the computer tested. Supposedly there is no charge for testing. Use 2nd link if not near an Apple Store or aren’t in the US. Hardware Repair - Keeping Confidential Data Safe

Genius Bar Reservation US

Authorized Service Provider

Nop, nothing is working, 10.12.4 completely fried my macbook pro

Tried the lot

- resetting everything

- efi loader

- all the startup options

nothing.. until..

my MBP came with a shiny disk, never used but seems to do the trick.

rebooted with option to CD (really!) and noticed with diskrepair the partition was not activated, decided to do a clean Leopard install.. much happier now.

perhaps 10.12.4 cannot handle the diskchange I did after HD failure a while ago?

I Reformatted my mbp and used Time Machine to go back to a 10.12.3 backup.

Sent a comment to Apple about problem, but after reading so many issues experienced by others, I am waiting on a newer update and will consider it

Us too. I am an experienced mac admin. It will not go to safe mode. It will allow picking a disk with the option key, when I choose a boot up drive as the Mavericks (or Sierra) install USB, it does the same thing - to grey. Resetting PRAM, SMC, nothing helps.

You can get it running by getting rid of all the video drivers. It requires about 10 mins booting into single user mode and moving the ati and amd video drivers to a place where they will not load. On mobile here but the instructions can be found by googling crsutil disable and video and recovery mode

Had some discussion with an apple tech whi contacted me asking for the verbose log. After giving it there's a deafening silence from him despite effort from my side. Guess it's sweep it under the rug time again. Because a mac is entirely propriatary you will depend entirely on apple willing to help you. In this case apple breaks your mac with an update, but will not take any responsibility for it.

High end? Perhaps in name.

Thanks Andrew!

Not for the faint of heart: Assumes ATI/AMD video

1) disable SIP

https://www.igeeksblog.com/how-to-disable-system-integrity-protection-on-mac/

NOTE - You have to boot with command - R - S to get into single user recovery mode.

After you disable SIP, type reboot or exit to get the SIP disabled

2) Boot into single user mode

3) Remove the AMD video drivers

https://apple.stackexchange.com/questions/261684/disable-sip-without-recovery-mo de/276433#276433

http://www.insanelymac.com/forum/topic/236869-how-to-ati-hd-4350/

Kext moving trick: (linked to from post #1)

This moves all ati kexts to a folder named 'kext_backup' at the root of your drive. It can get your card to boot into a basic graphics mode (VESA) if safe mode etc isnt working.

HOW TO MOVE THE KEXTS FROM SINGLE USER MODE:

Type flag at boot: -s and press enter. Then type this at boot, pressing enter at the end of each line:

/sbin/mount -uw /
mkdir /kext_backup
mv /System/Library/Extensions/ATI* /kext_backup
rm -rf /System/Library/Caches/com.apple.kext.caches
reboot

IF IT WORKS:

it will boot up into a horrificly low resolution vesa desktop

hooray you have succeeded!

I recommend getting your main OSX installation running perfectly before trying to get proper graphics support for your secondary installation. Only then revert the kext moving.

You can revert it easily in Finder by moving the ati kexts from /kext_backup/ to S/L/E, and running pfix.

IF IT DOESNT WORK:

you can revert the kext moving from single user mode.

TO REVERT THE ATI KEXT MOVING FROM SINGLE USER MODE:

boot into single user mode again (flag -s at boot) and type these commands:

/sbin/mount -uw /
mv /kext_backup/* /System/Library/Extensions/
chown -R 755 /System/Library/Extensions/ATI*
chown -R root:wheel /System/Library/Extensions/ATI*
rm -rf /System/Library/Caches/com.apple.kext.caches
rm -rf /kext_backup
reboot

Now your computer will be really slow, as there are no video drivers so the OS falls back on 'CPU drivers'. This technique got a 2011 iMac running again. The computer runs, well enough to backup and well enough for light tasks, but the video is sometimes a bit garbled, etc.

I think this is a bug in Apple's video drivers. I don't know how they can fix it except with a USB key that one would boot off of to install a fix. Hopefully someone can perhaps make an installer for video drivers from 10.12.3 that **work**.

*** with these standard answers? none of them are helpful, obviously the problem is in the recent update

Similar issues were before the previous update which fixed the accidental rebooting.

Similar happened to me. After multiple restarts I was able to complete the install and sign in to my computer. Now I have no audio and submitted a question to try to get it resolved.

Nop, nothing is working, 10.12.4 completely fried my macbook pro

Had the same issue with late model 2009 iMac. Reinstall OS X from recovery mode fixed the problem. Thank you

can't even get to recovery mode, booting from cd does not work, can get to the apple hardware test and after an hour it says no errors found.

other suggestions?

NOTHING worked for me, 10.12.4 killed my macbook, this is what you get with all proprietary, ther are no repair or upgrade possibilities.