Failed on Mac Mini – possibly due to Sophos AV…..

Searched….. and found…..​

10 Most Common macOS Sierra Problems and How to Fix Them

#1. macOS Sierra Upgrade Shows “An Error Has Occurred” Or “Failed to Download”

This is a common issue that many users face while upgrading their Mac to a new operating system. The solution is quite straightforward and easy to tackle.

To fix this issue, you have to delete the existing macOS Sierra installer and re-download it. To do so, open Launchpad and you should see the half-downloaded “Install macOS Sierra” file with a question mark on it. Delete this file, reboot your Mac and retry the download process.

#2. Mac App Store Shows macOS Sierra as “Downloaded”

If you go to the Mac app Store and see that macOS Sierra is shown as “Downloaded”, then it means that you either have installed the beta version or the GM build.

To be able to download the final version of macOS Sierra, you have to remove any existing “Install macOS Sierra” installer files from your Mac or from a connected hard drive. Once you’ve removed the installer files, go back to the Mac App Store and you should be able to install the final version.

#3. “This copy of the Install macOS application is damaged, and can’t be used to install macOS” Error

If you see this error while attempting to download and install macOS Sierra, it means that the file is either corrupted or was interrupted during download.

One way to fix it is to delete the “Install macOS Sierra” file from Launchpad, reboot your Mac and download the macOS Sierra file again.

#4. Wi-Fi Problems

OS X Wi-Fi icon

Internet connection and Wi-Fi problems are the most annoying issues anyone could face while using a new operating system. Some users have reported that webpages, including downloads, load very slowly after upgrading to macOS Sierra.

Firstly, you have to ensure that there are no issues with your router and that your ISP is providing a proper internet connection. If these two have no issues then you can try deleting your WiFi preferences and start afresh. To do so, read the steps below:

  • On your Mac, open Finder.
  • Select Go from the top menu and choose Library (you have to press the Alt key while the menu is open so that you can view the Library option).
  • Go to /Preferences/SystemConfiguration/.
  • Delete the following files:
    • NetworkInterfaces.plist
    • preferences.plist
  • Next, reboot your Mac and router.

#5. macOS Sierra Installation Freezes or Crashes

macos sierra installation freezes or crashes

If your Mac freezes while installing macOS Sierra or the installation crashes, then there are a few methods to fix this annoying problem.

  • The first thing to do is to disable or uninstall any Antivirus software that is present on your Mac, as they may interfere with the installation.
  • Ensure that you have a proper and reliable internet connection.
  • Next, you can try installing macOS Sierra in Safe mode. To do so, switch off your Mac by holding the Power button until it shuts down. Next, turn it on and when you hear the startup sound, hold down the Shift key. When the Apple logo appears, release the Shift key and your Mac should now be in Safe mode. Now proceed with installing macOS Sierra.

#6. Not Enough Space to Install

It can be annoying if your macOS Sierra installation is interrupted just because you don’t have enough space to install the new operating system.

You have to make sure that you have at least 8GB of free space available on your Mac. So get rid of all the junk files and delete unnecessary files and apps. If the error still appears after clearing up some space, then try installing macOS Sierra in Safe mode.

  • Next, you can try installing macOS Sierra in Safe mode. To do so, switch off your Mac by holding the Power button until it shuts down. Next, turn it on and when you hear the startup sound, hold down the Shift key. When the Apple logo appears, release the Shift key and your Mac should now be in Safe mode. Now proceed with installing macOS Sierra.

#7. Lag & Other Issues with Logitech Mouse


Unfortunately for users of some Logitech-branded mice, the update to macOS Sierra has broken compatibility, and has caused a series of issues in their accessories. Some of those problems include “laggy” response times, and some customizable buttons flat-out not responding at all.

The issue stems from a lack of compatibility between macOS Sierra and Logitech’s Control Center app. The latest release for the Control Center app, version 3.9.4, specifically mentions that the M705’s forward and back buttons are not working, and scrolling was “problematic” as well.

Therefore, you have to wait until Logitech releases an update to fix the issue.

#8. Mac Won’t Turn on after Installing macOS Sierra

If you’ve installed macOS Sierra, but your Mac isn’t starting, you can try resetting the NVRAM and PRAM. To do so, restart your Mac and then hold down the Cmd + Option + P + R keys together until you hear the startup chime sound twice. After the second chime sound, release the keys and your Mac should hopefullly boot up without any issues.




#9. Installed Apps Show ‘Damaged and Can’t Be Opened’ Error

how to fix Damaged and Can't Be Opened error

If you have updated to macOS Sierra and get a ‘Damaged and can’t be opened’ error when trying to launch an app, you should make sure that the app has been updated to the latest version.

If the issue still persists after updating the app to the latest version, remove it from your Mac and install it again.

As a last resort, if nothing else works, you can clear the cache.

  • Open Finder.
  • Click ‘Go’ from the top menu and choose ‘Go to Folder’.
  • Enter ~/Library/Caches into the text box.
  • Delete the files from every folder.
  • Now, repeat the same process for /Library/Caches (without the ~ symbol)

Reset the PRAM by restarting your Mac and holding down Cmd + Option + P + R keys.

Even after all this, if the problem still persists, then try launching the faulty app while holding Cmd + Option keys.

These are some of the most common issues that users are facing after upgrading their Mac to macOS Sierra. For most, it has been a seamless experience and we hope that this article will clear out all the issues you’re facing with the new operating system.

What problem are you facing with macOS Sierra? Let us know in the comments below.

#10. iCloud Error and Authentication Issues

Some features and functionality of macOS Sierra depend on iCloud and you’ll be asked during the setup process to enable some of these features such as Storage Optimization and iCloud Documents and Desktop. You can skip them if you want but an annoying issue that some users are facing is that iCloud constantly pops up for authentication or displays an error.

For instance, you may get an ‘Error connecting to iCloud’ popup or see something like ‘This Mac can’t connect to iCloud because of a problem with …’. To fix these issues, do the following steps:

  • Open the  Apple menu and choose System Preferences.
  • Select iCloud and click on ‘Sign Out’.
  • Next, reboot your Mac and open the iCloud preference pane again.
  • Sign in into your iCloud account.

Have you hit any of these issues while upgrading to macOS Sierra? Please share your experience in the comments below.​

macOS Sierra Installation Issues
Tagged on:     
%d bloggers like this: