MacOS Sierra Common Problems and Solutions

1. • Most Common macOS Sierra Problems and Solutions
• The major update to Apple's Mac OS X, is no more OS X 10.12, instead,
it's named macOS Sierra.
• Some users will painfully encounter a slew of macOS Sierra
problems/issues, like macOS Sierra download problem, macOS Sierra
supported Macs etc. This list of macOS Sierra problems and solutions
will show you how to fix the most common macOS Sierra update
problems on MacBook, iMac and other Apple computers, including
macOS Sierra upgrade failed, install stuck, slow Mac performance etc.
• Sierra Bricked Mac Completely
• A bricked Mac means it won’t boot up at all. This is very rare, but there
are varying reports online of Sierra just outright bricking a Mac after a
failed install.
• If this happens, you’ll almost certainly need to initiate a reinstall process
of macOS or Mac OS X, though some users have had to go so far as to
take their computer to an Apple Store for hands-on support.
macOS Sierra issues: macOS Sierra install frozen/stuck
• Some users will suffer a setback at the first step as they have problems
with macOS Sierra installation/download. The macOS Sierra installation
freezes at 30 minutes on MacBook, macOS Sierra gets stuck on install at
90%, macOS Sierra installation stuck on grey screen... if you have any
problems updating from El Capitan to macOS Sierra on MacBook Air/Pro,
iMac, try the fixes below:
• Get rid of any antivirus software installed on your Mac.
• Make sure you have created a Time Machine backup on hard drive.
• Press the power button and hold down the Shift key.
• Try updating software in Safe mode.
• Switch from wireless connection to hardwired connection.
.
• macOS Sierra update problems: macOS Sierra won't start up after
update
• After successfully install macOS Sierra without problems, some users get
stuck at the reboot: macOS Sierra issues with first boot up. Some
MacBook/iMac get a white screen with an Apple logo after macOS Sierra

2. update, while some other macOS Sierra boots get stuck on black screen.
It your macOS Sierra boots to black screen or Apple logo, here is how to
fix macOS Sierra update problems with white screen on reboot:
• Restart the Mac and hold down Command, Option, P and R to reset the
NVRAM.
• Reset the System Management Controller: shut down Mac > unplug all
cables from Mac > wait for several minutes and plug the cables > start up
the Mac.
• Try to boot Mac in Safe Mode and make sure you Mac has at least 9 GB
of free space.
• To avoid any problems updating from El Capitan to macOS Sierra,
remove all third-party Kexts and extensions.
• Problems with macOS Sierra: Mac apps can't be opened or damaged
• macOS Sierra update problems: slow macOS Sierra performance
• "My Mac runs very slow after update to macOS Sierra, it's supposed to
make my Mac run faster..." It's really annoying to have slow performance
problems updating from El Capitan to macOS Sierra, but not a few users
are crying about the macOS Sierra running slow issues "Word, Safari,
Preview, and iTunes wouldn't open- they froze and I had to force quit". If
you unfortunately have the macOS Sierra problems, here are some
solutions to speed up Mac macOS Sierra:
• If everything on Mac is slow, first try to restart Mac to see if it helps.
• Reduce RAM usage or upgrade RAM to make the computer run faster.
• Try to delete log file manually in the following folder (Command + Shift +
G): ~/Library/Containers/com.apple.mail/Data/Library/Logs/Mail/.
• Repair disk permissions with Disk Utility.
• Run SMC and PRAM resets on Mac.
• macOS Sierra upgrade issues: slow Wi- Fi
• Users who have upgraded to macOS Sierra frustratedly find that the Wi-
Fi on Mac gets extremely slow. "After installing El Capitan to macOS
Sierra, my Wi-Fi is so so so so so slow." If your Wifi connection is poor or
dropping frequrently, you're not alone. Check the slow Wifi macOS Sierra
problems and solutions for MacBook Air/Pro, iMac below:
• Delete the current Wi-Fi preferences: Create a new folder > Turn off Wi-Fi

3. > hit Command+Shift+G to get Go to Folder command, and choose the
following path:
• com.apple.airport.preferences.plist
• com.apple.network.identification.plist
• com.apple.wifi.message-tracer.plist
• NetworkInterfaces.plist
• preferences.plist > Move them to the new-created folder and reboot Mac.
• Power off/on your router and check if it needs any firmware updates.
• Reboot your Mac in Safe mode and reboot it again.
• Deselect Proxies: System Preference > Network > Advanced > Proxies
Tab; under "Select Protocol", uncheck any box if checkmarked; click
"OK" then "Apply".
• Turn off Bluetooth.
• macOS Sierra update problems: Bluetooth Not Available
• When you try to transfer file via Bluetooth on MacBook Air, MacBook Pro
or iMac, only to get a message stating "Bluetooth not available". This is
also one of the most-common problems with macOS Sierra update.
When you run into macOS Sierra Bluetooth not working problem, let's fix
it:
• Delete Bluetooth Preferences: In OS X Finder, press Command+Shift+G >
find type /Library/Preferences/ > find com.apple.Bluetooth.plist > delete
the file and shut down Mac.
• Reset SMC & Power Functions.
• Power off the system, disconnect all peripherals, and power on after 2-5
minutes.
• macOS Sierra upgrade issues & fixes: fast battery drain
• Some users are having bad battery life problems updating from El
Capitan to macOS Sierra. "100% charged battery drains fast on Sierra for
2 - 3 hours only. Before the mac OS Sierra upgrade, it could stay for 8-9
hours," as an Mac user complains. If you have installed macOS Sierra
and noticed that the battery life drains very fast on MacBook Air/Pro,
iMac etc, this may be because that the Spotlight uses more power. Here
are several solutions to macOS Sierra problems with bad battery life:
• Turn Off Spotlight Indexing as it keeps using significant battery.
• Switch browser to Safari from other third-party browsers.
• Adjust the Energy Saver settings.

4. • Check your Wi-Fi settings and disable Bluetooth.
• Reducing screen brightness.
• Reset the System Management Controller.
• Some users also report iPhone fast battery drain, here's how to save
iPhone battery.
• macOS Sierra problems and solutions: mail problem
• Following upgrade to macOS Sierra, some users experience mail not
working problems on macOS Sierra, including mail won't open, mail can't
verify account name and password, can receive but can't send email or
mail crashes problems. To fix macOS Sierra update problems with mail,
try:
• Deleting the email account in preferences, and create a new account to
see if that fixes the issue.
• Go to Preference and select Accounts > select Account Information >
find SMTP Server > select option "edit STMP server list" > reset all the
settings in the list.
• Uncheck mail extensions at Mail Menu > Preferences > select Extensions.
• Problems with macOS Sierra upgrade: external hard drive/SD card
not showing
• "I did the macOS Sierra upgrade and since then - my two external disks
won't show up! They don't show up in Finder, Disk Utility or on the
command line." Many other users are suffering from problems updating
from El Capitan to macOS Sierra with their external hard drive or SC card,
like disk not ejected properly, external hard drive not mounting...
solutions to macOS Sierra problems are as follows:
• Restart Mac (remove SD card and unplug hard drive before you restart) to
see if it fix this common macOS Sierra problem.
• Try to mount the Hard Drive in OS X Finder.
• 3.. Try third party drovers, TEXERA NTFS and PARADON NTFS to
connect the external disks to Mac system.
• Try to reset the SMC and the PRAM on your Mac.
• macOS Sierra update issues: freezing/crashing using Safari
• "My MacBook Pro has been randomly freezing and sometimes crashing
during normal operation and while using Safari, annoying." It's one of the
most common issues with macOS Sierra that after updating from El
Capitan to macOS Sierra, the updated Mac keeps freezing and crashing.
To solve macOS Sierra update frozen problem, try solutions below:

5. • Clearing the Safari history and cache: find
Library./Caches/com.apple.Safari/Caches.db and move it to the trash.
• Temporarily switch Safari to third-party browser such as Chrome, Firefox
etc.
• As a new operating system for Mac, it's a common occurrence to have
some problems with macOS Sierra and Apple will strive to solve any
known macOS Sierra problems with new release. And we will try to
gather helpful fixes to macOS Sierra update problems before the official
fix is released. This list of macOS Sierra problems and solutions will be
continuously updated to cover any latest issues with macOS Sierra. We
also gathere all the iOS 10 update issues tips for Apple users.
• For most users, installing macOS Sierra has gone without a hitch and
they’re left with a trouble-free Mac that works great with the latest
macOS system software release. But, not everything goes smoothly for
everyone, and sometimes updating to macOS Sierra can lead to a variety
of problems.
• We’re compiling a list of common problems in this troubleshooting guide
to remedy issues with the macOS Sierra download, installation, update,
and post-install process. Unfortunately for me (but fortunately for you
readers), I personally have had the joy of encountering many of these
problems during and after updating one particular MacBook Pro to Mac
OS Sierra 10.12, so I have very recent extensive firsthand experience with
troubleshooting much of what is covered here.
• To be perfectly clear this is meant to be a compilation for potential issues
experienced with the macOS Sierra update process. Most of this will not
be encountered by the average user, and is in no way suggestive of what
to expect during the Sierra update or installation process. The vast
majority of Macs update to macOS Sierra without any adverse incident.
• macOS Sierra Download Stops with “An error has occurred” or
“failed to download”
• Sometimes when users attempt to download macOS Sierra from the
Mac App Store they will confront a “An error has occurred” red message
and the download stops.
• The solution to this is fairly straight forward: Delete any existing Sierra
installers, whether they are half-downloaded or not, reboot the Mac, and
try again.
• Unable to Download macOS Sierra, shows as “Downloaded”

6. • If the Mac App Stores shows that “macOS Sierra” has “Downloaded” and
the button is not possible to click again, you likely had one of the beta or
GM builds and you will need to remove any existing “Install macOS
Sierra” application installers from the Mac, or any connected drives. That
last part is critical, because it appears the Mac App Store has no trouble
locating a named “Install macOS Sierra.app” located on an external
volume. Yes this includes even the GM builds which share the same
name as the installer app, and prevents the installer from downloading
again.
• Error “This copy of the Install macOS Sierra.app application is
damaged, and can’t be used to install macOS.”
• Something happened during the installer download where it was either
interrupted or became corrupted. Typically this means the internet
connection was disrupted, or the file itself somehow was interfered with
during the transfer.
• You will need to delete the “Install macOS Sierra.app” and download it
again from the Mac App Store.
• MacOS Sierra Wi-Fi is Dropping or Unusually Slow
• Some Sierra users have found wi-fi drops or is abnormally slow. If this
applies to you, you will likely need to trash the wi-fi prefs and then create
a new network location to resolve wireless networking problems like this.
We have a detailed guide to fix wi-fi problems with macOS Sierra
here.
• Read how to fix wi-fi problems in macOS Sierra
• The good news is that wi-fi trouble is usually really easy to fix and the
above article details specific steps to take which remedy the vast majority
of wireless networking difficulties.
• macOS Sierra Boots to Black Screen, Stuck on Black Screen
• Some users have discovered that macOS Sierra will boot to a black
screen and get stuck, unable to go further. This gives the appearance
that the Mac is off, but it’s actually on and the screen is just stuck dark,
with the Mac doing who knows what. This can happen right after the
initial installation, but also during a standard Mac system restart after
having updated to Sierra. I personally experienced this in the latter
scenario during a regular reboot, and as you can imagine it’s fairly
annoying to discover the Mac won’t boot up normally. Fortunately with
prior experience handling a similar issue, I was able to resolve it with the
following steps in this order:
• Disconnect all USB cables and USB devices from the Mac, aside from a
mouse or keyboard if applicable

7. • Shutdown the Mac
• Reset SMC
• Reset NVRAM/PRAM
• Boot as usual
• It may not be necessary to reset both PRAM/NVRAM and SMC, but since
you’re already doing one you might as well do the other. You’ll lose a few
basic power settings by doing so, but it’s not a big deal, and it resolved
the stuck on black screen issue for me.
• Some MacOS Sierra users have reported similar issues with their Mac
getting stuck on a black screen when waking from sleep. Often the same
SMC and NVRAM reset procedure remedies those difficulties.
• Unable to Shut Down macOS Sierra, Unable to Reboot macOS Sierra
• There appears to be a bug for some users that prevents the Mac from
using the  Apple menu Shut Down and Restart services. Selecting the
menu items results in no activity and no action, the Mac does not reboot
and it does not shut down.
• Sometimes a third party app can be holding up the shut down and restart
service, however. If you suspect this is the case, quit out of all open apps
before attempting to shut down or restart the Mac. You can also try
disconnecting all external devices, which has been reported to help some
users shut down MacOS Sierra.
• The other option is to forcibly shut down and reboot the Mac by holding
down the Power key. The forced shut down and forced reboot procedure
is a measure of last resort and should not be used as a means of initiating
any normal restart or shut down process.
• Some users have resolved the hanging on shutdown issue by rebooting
into Safe Mode. Booting a Mac into safe mode is easy, just hold down
the SHIFT key on system boot until you see the bootup progress bar,
then let go. Safe Mode will clear out some caches and disable some
functionality, but it can often be a helpful troubleshooting measure.
• Constant iCloud Error and iCloud Authentication Pop-Up Messages
• Many components of macOS Sierra are dependent on iCloud, and during
the initial setup process you’ll be asked to enable various iCloud features
including Storage Optimization and iCloud Documents and Desktop.
Whether you want to use all of those features or not is up to you, but an

8. odd side effect encountered by some is constant iCloud error messages
and pop-ups to authenticate.
• Two persistent popups that I was running into were “This Mac can’t
connect to iCloud because of a problem with (email address)” and “Error
connecting to iCloud”.
• I was able to fix the iCloud errors and make them go away by doing the
following:
• Go tot he  Apple menu and choose System Preferences
• Go to “iCloud” and click on “Sign Out”
• Reboot the Mac
• Return to the iCloud preference panel ( Apple menu > System
Preferences) and log back into iCloud
• After logging out and back into iCloud, the iCloud error pop-ups went
away.
• Safari Can’t Find Server, Unable to Load Webpages, Links Don’t
Work, Can’t Render CSS
• Some users are reporting that Safari is problematic after updating to
macOS Sierra, where links don’t work at all, or you type a URL into the
address bar and hit return and nothing happens.
• If you experience the unresponsive URL issue issue, you can empty
caches in Safari for Mac, then quit and relaunch the app and it should
work fine again.
• Another separate problem with Safari in macOS Sierra seems to be
sporadic difficulties loading webpages and contacting servers, leading to
an inability to load any webpage at all.
• A quick side note: the “can’t find server” message can be due to wi-fi
dropping, so if the connection difficulties are not limited to Safari you may
want to use the wi-fi fix mentioned above.
• Another odd variation of this is Safari failing to load webpages repeatedly,
but after persistent refreshing, Safari may be able to successfully load a
webpage but minus CSS (CSS being what styles the majority of
webpages).
• Additionally, another oddball Safari problem is when the browser URL bar
and buttons vanishes entirely and no webpage loads at all.
• Sometimes quitting and relaunching Safari will remedy these issues, but
usually you will need to reboot the Mac to get Safari working again for a
while.

9. • Another unusual error message you may encounter with Safari problems
in macOS Sierra is an inability to load a webpage, where the tab or
window renames itself to “Resources” and you get a blank page loading
stating: “Your copy of Safari is missing important software resources.
Please reinstall Safari.”
• Since you can’t really “reinstall Safari” in macOS Sierra, the error
recommendation is not particularly helpful, and instead you’ll likely want
to reinstall all of macOS Sierra or revert to the prior Mac OS version from
a backup.
• Spotlight Doesn’t Work with macOS Sierra
• Some users, myself included, have noticed that Spotlight just stops
working entirely at random in macOS Sierra 10.12. Sometimes Spotlight
will sort of half-work, but the results returned are completely inaccurate
and don’t match the search term. This is not because of indexing,
mdworker, or mds, however. You can kill the Spotlight process, it will
spin back up, but the Spotlight search ability does not regain
functionality.
• The only way to return Spotlight functionality in this situation is to reboot
the Mac. Inconvenient, a bit Windows-esque, but it works.
• You can also try to rebuild the Spotlight index directly, but you’ll still
likely need to reboot the Mac to have Spotlight start working again as
expected.
• Mouse Not Working, Mouse Functionality is Erratic with macOS
Sierra
• Some users have discovered their mouse is not working at all, or the
mouse may be working erratically after updating to macOS Sierra. For
example, the scroll wheel functionality may become unresponsive or not
work as intended. Some of these mouse issues have been narrowed
down to Logitech and Razor brands, perhaps pertaining to drivers or
software, but some of the erratic mouse behavior can occur with generic
USB mice as well.
• One possible fix for these issues is to connect the USB mouse directly
into the Mac, rather than going through a USB hub.
• Mac is Hot, Mac Fans Running at Full Speed After macOS Sierra
Installation
• If the computers fans are running after updating to MacOS Sierra and the

10. Mac feels hot to the touch, it’s very likely to because the Mac is indexing.
This is not indicative of a problem in and of itself, and it’s perfectly normal
for the Mac to require reindexing the entire hard drive for features like
Spotlight and Siri to work. Additionally, the new Photos app for Mac
index the Photo library to identify places, features, faces and people, and
other landmarks, which can also take a while. It’s also likely that Time
Machine will be running to backup the Mac again after updating the
system software. Just let all of these processes complete, do not
intervene.
• Thus, if the Mac is running warm or the fans are blazing away after
updating to macOS Sierra, the best thing you can do is simply wait. The
vast majority of the time the indexing process simply needs to run and
complete, and the Mac will become usable with low fan usage and a cool
temperature again.
• For most users this process can take an hour or so, but with many
documents or Photos, it can take quite a bit longer. If the Mac is still
misbehaving after leaving it to index overnight, open the “Activity
Monitor” application (found in /Applications/Utilities/) and sort by CPU, so
that high CPU usage is at the top. This will tell you what (if any)
applications or processes are consuming the processor and could give
you an idea of where to look to troubleshoot further, which is typically an
errant task or process.
• macOS Sierra Video Problems, Hypercolor Rainbow Display
Craziness
• This is a weird one that I experienced on a Retina MacBook Pro: the built-
in display suddenly encountered severe video display problems, ranging
from improperly rendered drop-shadows to – and here’s where it gets
really out there – psychedelic hypercolor rainbow display oddness,
permeating throughout various onscreen elements.
• In addition to the psychedelic color experience, dropshadows and other
UI elements would appear obviously broken and display errantly:
• Here’s a brief video demonstrating what the crazy video situation looks
like on a Retina MacBook Pro display when it’s changing wallpapers:
• macOS Sierra Video Problems, Crazy Color Display
• Enable JavaScript if it is disabled in your browser.</div></div>

11. • The solution? Another SMC reset.
• Finder Not Responding, Apps Crashing Constantly, Apps Won’t
Open, Constant Beachballs
• Finder not responding? Apps not responding? Apps won’t open? Apps
say they are damaged? Constant inappropriate beachballs for no
apparent reason? Well, you can temporarily remedy these issues by
rebooting the Mac. And then rebooting the Mac again. And again.
• But here’s the bad news; if you are experiencing those type of issues
consistently and have to reboot once or twice a day as a temporary
workaround, you should give in and reinstall macOS Sierra.
• Speaking from direct experience, I battled and troubleshooted for several
days the unresponsive apps, apps unable to open, inappropriate beach
balling, but no matter what I did, no matter how many caches and app
data was trashed, whatever troubleshooting hoops I jumped through, the
problems returned in a matter of time after the next reboot.
• “The application ‘name’ can’t be opened” or Error -41
• A variant of an aforementioned error message where apps don’t open is
when the application reports a direct error message when trying to open,
often in the form of an onslaught of error pop-ups stating “The
application (name) can’t be opened” and sometimes accompanied by an
“Error -41” message pop-up message. This seems to occur after macOS
has
• The only solution to this particular meltdown of macOS Sierra is to reboot
the Mac. If you continuously experience this error or variations thereof it
is likely a good idea to wipe the drive and clean install macOS Sierra.
• Kernel “File: table is full” Errors Filling Console Log
• On some user configurations, there appears to be a problem with Mac
OS not properly closing files, though it is unclear what the cause or
solution is. Eventually this can lead to “kernel file: table is full” errors
flooding the Console log, requiring a manual forced reboot.
• Troubleshooting Difficult macOS Sierra Problems
• One of the best ways to troubleshoot some of the aforementioned
unusual or more difficult Sierra problems is to create a separate
Administrator user account on the Mac, and use that new separate

12. account exclusively for a few days while performing regular computing
activities. The reason for this is quite simple; if the problem does not
occur on a separate user account, it suggests the underlying cause is
related to the other user account, perhaps in the form of a corrupt
preference file or a process that is unique to that user account.
• The key is to create a brand new user account, then log out of any
other user accounts on the Mac. Only use the newly created user account
as you attempt to reproduce the problem.
• Open System Preferences from  Apple menu and go to “Users &
Groups”
• Add a new user, named something obvious like “Troubleshooting” and
set as Administrator.
• Log out of the existing user account (and log out of any other user
accounts as well)
• Log into the newly created Administrator test account and try to
reproduce the difficulty here
• If the problem still occurs in the new user account, it suggests a deeper
issue with the Mac OS systems software, an underlying system-wide
process, or even the specific installation of MacOS.
• Backing up thoroughly and then performing a clean install of macOS
Sierra may offer a resolution or improvement to an issue that is
reproducible from a new fresh user account.
• If the problem returns after a clean install, there may be an outright bug
with macOS, or there may be a problem with the Mac itself. If possible,
contact the official Apple Support channels for further assistance.
Downgrading macOS Sierra to El Capitan or Mavericks
• Disconnect Peripherals, Quit Apps, Try Again. Does the Problem Still
Occur?
• Another common troubleshooting technique for various issues is a
process of elimination.
• Try disconnecting all peripherals (except a mouse and keyboard if
applicable). Does the problem no longer occur? If so, this could suggest
some sort of issue with third party peripheral compatibility. It’s rare, but it
does happen. Contacting the vendor who made the problematic

13. peripheral may lead to a solution.
• Next, try quitting all apps, and using each app one at a time. Does the
problem still happen? Does the problem only happen with one specific
app running, and not others? If so, this may be indicative of an issue with
the specific app that is in use. Perhaps it needs to be updated to support
Sierra, and contacting the developer of the app may be worthwhile.
• The process of elimination works well in conjunction with the new user
account method outlined before this. Sometimes it’s just a matter of
narrowing down a problematic app, process, accessory, and sometimes
that can only be done through trial and error.