The new macOS Sierra update is now available to download and install for OS X 10.11 El Capitan users, but if you’ve just decked out your Mac with the latest operating system and noticed that things don’t work the way they should, or encounter any other issues, then we have a list of fixes for the most common problems.
Inevitably, when there’s a new release of an operating system there are going to be problems, but don’t let the list below put you off, as most people should find the process of upgrading to macOS Sierra pretty painless. If you haven’t upgraded already, check out our guide How to download macOS Sierra.
If you do experience any problems with macOS Sierra, then don’t worry – you’re not alone, and we’ve collected solutions to the most common issues to help you get your Mac working just the way it should.
macOS Sierra problems: macOS Sierra freezes or crashes when installing
If your Mac crashes or becomes unresponsive while installing macOS Sierra, then there are a few things you can try to fix the problem.
Before installing macOS Sierra, uninstall or disable any antivirus software on your Mac, as that may be causing issues.
Press the power button on your machine while holding down the Shift key on your keyboard. Boot your Mac into Safe mode, then try installing macOS Sierra again. It might also be worth switching from a Wi-Fi connection to a wired connection before you download and install.
macOS Sierra problems: macOS Sierra won’t start
If you’ve installed macOS Sierra, but your Mac won’t start, then restart your Mac and hold down Command, Option, P and R, which will reset the NVRAM (non-volatile RAM).
Hold the keys down until the computer restarts and you hear the startup chime for the second time. Release the keys after you hear the second startup chime. The PRAM will be reset as well.
For other ways to fix a Mac that won’t start, check out our guides How to Use OS X boot options to troubleshoot your Mac and How to fix a Mac that won’t start.
macOS Sierra problems: Mac runs slowly after macOS Sierra upgrade
If your Mac is running noticeably slower after upgrading, there are a number of things you can try to speed up macOS Sierra.
First of all, try restarting your Mac to see if that helps. If it doesn’t, force-quit any apps that appear to be taking up a lot of RAM. You can identify these by using Activity Monitor (in /Applications/Utilities) to establish what apps and processes are using up the most CPU or RAM. Its CPU tab lists active processes, with a real-time view of what’s going on.
To force-quit an item, click it in the Activity Monitor list, then click the X at the left of the toolbar, then confirm you want to force-quit.
Also delete the cache. Open the Finder window, select ‘Go’ from the top menu and select ‘Go to Folder’.
In the text box that appears type /Library/Caches
Remove the data from inside every folder. Now repeat the process with /Library/Caches (without the symbol). Running the Repair Disk tool from within Disk Utility may also help, and for more solutions check out our How to speed up your Mac guide.
macOS Sierra problems: apps show ‘damaged and can’t be opened’ error
Some users are complaining that they can no longer open certain apps after updating to macOS Sierra. Instead, they’re getting an error message that says the app is ‘damaged and can’t be opened’.
To fix this problem you’ll need to delete the cache in macOS Sierra. To do so, open up the Finder window, select ‘Go’ from the top menu and select ‘Go to Folder’.
In the text box that appears type /Library/Caches
Remove the data from inside every folder. Now repeat the process with /Library/Caches (without the symbol).
Clear the PRAM by restarting your Mac and holding down Command, Option, P and R on your keyboard.
If the apps are still struggling to load, hold down the Option and Command keys when you click the app’s icon.
macOS Sierra problems: slow Wi-Fi
If you’re experiencing slow Wi-Fi speeds after upgrading to macOS Sierra you may need to delete your current Wi-Fi preferences. These can be found in the following folders using the Go to Folder command (Command + Shift + G):
Reboot your Mac afterwards, as well as your modem or router.
macOS Sierra problems: some Bluetooth devices won’t work
Some macOS users are reporting issues with their Bluetooth devices connecting to their macOS-updated laptop or desktop. This can be due to Apple’s compliance with the Bluetooth Special Interest Group (SIG) outpacing Bluetooth devices that don’t adhere as closely to the SIG’s standards.
Power-cycling (i.e. running your devices to zero power and charging them again) all devices involved, including the Mac in question, can solve the problem.
If that doesn’t work, you may have to revert your Mac to El Capitan until the provider of said Bluetooth device issues a firmware update to said device. But, since most do not do this very quickly, you might be waiting a while.
Other macOS Sierra problems
As macOS Sierra has only just released we’re likely to see more issues emerge – although hopefully Apple will be quick to release fixes and updates to combat these problems.
Still, make sure you check this guide regularly, as we’ll be updating it with any new problems or issues we find with macOS Sierra.
If you’ve encountered a macOS Sierra problem that we haven’t covered here, let us know in the comments and we’ll try our hardest to find a solution for you.