10.12.6 update problems when restarting imac

Possible Fixes for El Capitan or Later

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 OS X El Capitan 10.11.6 Combo Update or Download macOS Sierra 10.12.5 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 Continue button.

I have experienced the same problem, with an MacBook Pro Retina 15", end of 2013. Blocked after restarting, again and again. I asked Apple support, and after several attempts (including the reinstallation of macOS) the only and final solution was to recover from Time Machine. Scaring, as it implies erasing the disk, as the first step. It has been successful, my mac is working again, but keeps asking for the installation of the upgrade. Again. Which I'll certainly not allow, for the time being. I've been trying to identify whether anyone else experienced this problem, as there's no "noise" on Internet, which surprised me. I would really appreciate having an "official" explanation for this problem, as I suspecte there's something wrong with this update.

This, again, seems to be a .kext Problem, meaning certain Kernel Extensions are not compatible anymore. Mine were Canon Printer .kext Files.

Procedure: Command R after it chimes at start-up.

Start Terminal.

Navigate to Volumes/Macintosh HD/Library/Extensions.

When I delete the BJUSB and CIJUSB kext Files, everything works perfect. Seems that the Canon v3.4 Update causes this (released at the same time: by Apple!). I find it very annoying, that printer drivers can mess up the system in that way. Happened to me before. Spent at least 4 days trying to fix this.

Intriguing! How could be identified which .kext are to be blamed? Is it there any trace of that?

I checked my Library/Extensions directory, and I've many I know neither its purpose nor the consequences of eliminating them.

Absolutely insane. Why are Apple users beta testers spending time to work out the problems with yet another Apple update that fails. For shame, Apple. The promise was Mac are ready to use. Another promise broken by the finest -- Apple.

Simply, Apple, this is not good.

Some of what I have since considering the update:

I worked out how to stop the kexts being replaced, I had automatic install of app updates turned on in my App Store preferences. I disabled it, in this case by turning off the automatic downloads:

I assume you could also do the same by leaving downloads on but unchecking "Install app updates".

Now I see this:

For now I shall ignore that update 🙂

I had the very same problem. I made the mistake of updating both laptops (MBP mid-2015 and MBAir 2013) to OS 10.12.6 Both were not able to fully boot afterwards. They sat there Apple logo burning bright and progress bar completed. And they sat there, and sat there...

I tried everything: PRam/NVRam reset, SMC reset, Disk Utility. nothing helped. Hardware test did not reveal any problem.

Command R did not help. I could repair the HD all I wanted to but it did not good. It would not boot in Safe Mode, Single use mode. I could not get to the point where I could make it to terminal.

I used the Verbose mode and it showed it booting until it hit the "SmartBattery: finished polling type #" - which it would repeat over and over again (about every minute).

I finally had to restore from my newest backup (using Super Duper).

OS 10.12.5 will be fine until the next major update.

Hi everybody,

I have an iMac 27-inch 2011 and I just found a solution to stop this (re)bootloop issue.

Sierra 10.12.6 was required for me to install the Nvidia Web Driver 378.05.05.25f01.

Because my graphic card is faulty, I can't press Shift at startup to start in Safe mode, so I followed Apple guide to reach it using command line (cmd + S at startup).

Just type the first command (see screenshot), and then "reboot". This will force your iMac to start in Safe mode.

At first reboot the boot failed as before, but after rebooting itself one time, the "installation remaining time" mention appeared again under the progress bar until the end and my iMac started successfully.

Don't forget then to open your Terminal and type the last command to reboot in normal mode.

I hope this will help :)

So this thread helped me solve my problem with the update yesterday, I'm very thankful to everyone who contributed.

I'll explain my problem and solving process here, in case this helps anyone else!

I'm using MacBook Pro (13-inch, Mid 2010), with a internal SSD drive and was previously running Yosemite.

So, after encountering major problems years ago with updating to Yosemite, I was so weary of these System Updates that I just stopped doing them. Shortly after Sierra came out this past year, I thought I'd give it another shot and tried updating. Problem was as described above, so: download runs smoothly, installing does too apparently, then when trying to reboot, it gets stuck on the Apple logo with a full progress bar. No keyboard commandos (e.g. cmd + L) give any reaction. Turning off and the on again just turns out with the same full progress bar stuck in place.

That time I just desperately restored from Time Machine backup and went on using Yosemite.
Unfortunately after buying a new iPhone SE recently, I couldn't sync my phone with my iTunes version anymore and had to finally tackle this upgrade.

So I thought maybe the download via wifi left the install faulty and installed from a USB drive a friend of mine had successfully used multiple times before. Encountered the same problems. When the boot got stuck nothing worked (like booting in safe mode, or recovery mode). Luckily enough my friendly helper then unplugged the MagSafe connection and tried booting in Startup Manager (hold Option ⌥ key) again, which somehow now worked. So I could boot recovery mode after all. Now after browsing this thread it was apparent the .kext files were our problem.

We spent ages trying to navigate the Terminal but finally were able to speak its language. So this is what worked:

This code (from this thread):

cd "/Volumes/Macintosh HD" ; ls -1 Library/Extensions/ ; find Library/Application\ Support -iname *.kext ; find Library/Filesystems -iname *.kext ; find System/Library/Extensions -ctime +2d -depth 2

rendered a couple of .kext files (see picture) (after I exchanged "Macintosh HD" with the name of my drive!!!!). Initially we thought we'd only delete the hp one and the Epson one, since apparently those were the main problem. Did this and tried rebooting unsuccessfully. So deleted all the .kext files shown and tried rebooting again, which turned out unsuccessfull. However after running another reinstall I could boot and everthing seems to be working fine.

This is what I did to delete the files, for anyone who (like me) has no idea how Terminal works. (Also check pics for reference)

cd "/Volumes/Mac SSD/Library/Extensions" enter ("change directory")

ls enter ("list", this is just me checking I've accessed the right directory and which files are in there)
rm -rf file.kext enter (be sure to swap file.kext with the name of the file you want to delete)

In conclusion, I now have a working laptop and I couldn't be happier. I just don't know wether there'll be consequences from deleting all those .kext files that I don't know the use of.

mcsoundmac, if you go to the Apple Beta Software Program you can sign up and download the installer.

and if you go to https://9to5mac.com/2017/08/02/how-to-create-bootable-macos-high-sierra-usb-inst all-drive-video/ you can learn how to create a USB stick that will install the new beta for you.

before you do so, you might want to follow the instructions at https://www.imore.com/how-partition-your-mac to create the extra partition to install the new High Sierra beta safely, without affecting your current install of macOS Sierra. If you have more than 20GB available on your drive you could create a partition large enough to try High Sierra Beta and if you like it you can then get rid of you Sierra Partition to make your drive a dedicated High Sierra drive.

should be needless to say, I'll say it anyway, that you'll wanna make a complete backup of your current drive with everything on it...I love and use Carbon Copy Cloner, but you can even create a backup disk image of your current System dive with Apple's free and included Disk Utility app).

Thank you! That saved a lot of time. What I'm seeing now is that once the system is back up those files *reappear* which causes the next reboot to hang again. I don't think this is SIP as that would prevent me from removing critical system files rather than put them back once they're deleted.

I'm assuming it's either some Launch Daemon/Agent or perhaps some automagic updating of the currently defined printers. If I find the cause I'll share it here.

Elmusrati, I would bet that there are literally *millions* of Apple computers affected by this, considering that even an early-2015 MBP 13 (by user davesalvo) couldn't boot anymore after applying the update...that's one of Apple's most popular notebooks...and if this really does affect most/all pre-2015 machines then the sheer number of people would be devastating...*many* millions, I'd guess.

But since ******** and moaning here is not really going to get us anywhere, I looked up the best place to complain to Apple through official channels.

Feedback - macOS - Apple

Subject: 10.12.6 Update causes pre-2015 Macs to fail booting

Feedback Type: Bug Report option

Feedback Area: Installation/Setup

As Comment, I wrote the following, although I found that the comment box only allows for a certain amount of characters and truncated my message after "To think that something as simple as a printer software package can cause what would prob...", so I stopped after "...a glaring oversight in your beta-testing process." and finished it with "It's unbelievable, the damage in wasted time this has caused your loyal and new patrons!" Wish I could have sent the more lengthy part about our frustration and the preposterousness of it all, but maybe one of you could post that part (in your own words)…anyway, so this was my comment:

After weeks of testing and researching this issue, I am now certain that most (if not all) Apple computers that are pre-2015 (even though at least one user experienced this issue with an early-2015 MBP 13") will fail to boot after applying the 10.12.6 update.

Extensive communication and knowledge exchange on one of your forums (https://discussions.apple.com/thread/8019574?answerId=32083178022#32083178022&ac_cid=tw123456#32083178) has proven that this infuriating bug relating to some of the printer software kext files (notably the BJUSBLoad.kext and CIJUSBLoad.kext files) which, once deleted by means of booting into the recovery partition and using terminal to do so, appears to be a glaring oversight in your beta-testing process.

To think that something as simple as a printer software package can cause what would probably amount to hundreds of thousands (if not millions) of hours of your patrons’ time being wasted, some of your more inexperienced users possibly even losing irreplaceable data, is inexcusable. Frankly, I am appalled by what could possibly have gone wrong in your development process to catch this before the update was posted, and - even more puzzling - remain in your App Store without a warning or patch.

Please warn your users about this problem, or - better yet - fix the posted update.

Same problem here - MacBook Air Early 2014. Current version 10.12.5 - tried different ways:

- Update via AppStore --> after install the boot screen stucks (process indicator full)

- Update via separate downloaded update --> after install the boot screen stucks (process indicator full)

- Clean install of 10.12.6 sierra --> worked

--> recovery of time machine backup --> after install the boot screen stucks

- PRAM restored, clean install --> same behavior after time machine recovery... no way to get the MBair running with my programs installed and 10.12.6

I assume it something with the data from the TM backup.... but I don't see a way to see the reason for that 😟

Works for me, thanks a lot. I had a old dropbox and HP kexts, so i removed both of them, and now my macbook air (2012) reboots perfectly. I suppose some of these kexts are from older version of the OS, since i had never done a wipe since the first use of my mac. Thanks again.

Same here with a 2012 Retina MBPro :

- Update : stuck on the black apple loading screen when bar is full

- Reinstall 10.12.5 from Time Machine OK

- Tried clean install from recovery partition : stuck on the black apple loading screen when bar is full

- Reinstall 10.12.5 from Time Machine OK

I will try removing the Canon BJUSB and CIJUSB kext Files...