What to do if your Mac gets stuck during a macOS update

Installing new versions of macOS on a Mac should be a fairly simple practice. A Mac computer tells you about any available updates using a pop-up window in Notification Centre. In some cases (depending on your settings) it is already downloaded and only needs your authorization to be installed.

However, sometimes when you click on Go on an update, things don’t go as you expected. In this post we’ll explain what to do if your Mac stalls or freezes during an operating system software update. We’ll also explain what to do if you see the message “macOS could not be installed on your computer.”

There are some circumstances that can interrupt the installation process, such as a power cut or the lack of space available on your Mac (we always recommend that you don’t install anything with less than 10 GB free to avoid having problems with the installation). There may be other problems with your Mac, so it is worth running Disk Utility before updating.

It is always advisable to perform a standard series of checks before you perform an operating system update on your Mac. In this post though, we will only explain possible solutions to fix your Mac if it freezes or stalls in the middle of an update.

Can’t download the macOS update

If you haven’t even gone through the download stage, there are some things you can try.

1. Check Apple’s servers. When Apple releases a new macOS update, many people will rush to download it. This can cause problems with Apple’s servers. First, you should check that the update is available; also check the download speed. It may take a little longer than normal if there are thousands of users trying to download it at the same time.
2. Use a wired connection. A wired connection is always faster. If you switch from a Wi-Fi connection to a wired connection things will be quicker.
3. Cancel the download. You may be able to fix a stuck update by going to the Mac App Store, finding the software you are downloading and pressing Option/Alt. You can then start the download again without any problems.
4. Download the software from Apple’s support website. If you have problems downloading the update from the App Store, you can use Apple’s website. You can find the latest macOS updates here.

How do you know if an update has stalled?

If there is a problem with the software installation, your Mac will usually get stuck on the updating screen. The screen will show the Apple logo and a status bar that shows progress while the software is loading. The screen will also show a ‘spinning beach ball’:

You may see a white, grey or black screen (you may not be able to tell if the Mac is turned off or turned on). You must be sure that the installation isn’t running in the background because the forced reboot of the computer during an installation will interrupt the installation process and could cause data loss. This is one of the reasons why it is always advisable to make a backup before installing new software.

If your Mac seems to have frozen during installation, you should search for “signs of life” and follow the advice below:

1. Has your Mac really frozen? Before you conclude that your computer has frozen during the installation, you should consider something. Sometimes, updating the software on a Mac can take a lot of time (many hours). Your Mac may look frozen, but if you leave it for a few hours it could finally finish its task.
2. Look at the Log to see if your Mac is still installing OS X. Press Command + L. This offers additional information and more details about the amount of time still remaining for the installation to finish. It can give you a better idea of what files are being installed and the amount of time remaining to finish.
3. Wait. If it turns out that the installation hasn’t stopped, be patient and wait for a few more hours. Sometimes it’s worth leaving the Mac during the night to finish the work it has started. The time shown by the progress bar is not always reliable, but that doesn’t mean that it’s not busy trying to install the software.

What to do if your Mac freezes during software installation

If you are sure that your Mac is no longer working on updating the software, follow these steps:

1. Turn it off, wait a few seconds and restart your Mac. Press and hold the power button to turn off your Mac and start the backup.
2. Go to the Mac App Store and open Updates. If you were installing an application from the App Store, open the App Store and click Updates. You should find that the update/installation process continues from where it stopped.
3. R Check the Log screen to see if files are being installed. When the progress bar appears, press Command + L again to check the Log screen and make sure the files are being installed. If the Log screen shows that nothing is being installed, continue with the next step.
4. Try to install the Combo update. As we mentioned earlier, the Mac App Store is not the only place from where you can download Mac software. Apple still has software on its website, so you can download it from there. If you go to Apple’s support website, you can find a combo updater that includes all the files required to update macOS. This version will replace all the system files and, therefore, it will ensure that the update is complete.
5. Install in Safe Mode. Press the power button and hold the Shift key to start your computer up in safe mode. Then, open the App Store and update your applications while in Safe Mode. When you finish, restart your Mac.
6. Make space in your Mac. The reason the update failed might be that there wasn’t enough storage available to perform the installation. You should then delete some files in Safe Mode.
7. Reset the NVRAM. If Safe Mode doesn’t work, restart your Mac while holding down Command + Option + P + R. This will reset the NVRAM. Wait until your computer restarts and wait to see if the update starts.
8. Use Recovery Mode to reinstall macOS. As the last option, you can restart your Mac in Recovery Mode (hold down Command + R while starting it up). After that, there are different options to choose from: you can recover your Mac from the last Time Machine backup or perform a disk repair.
9. Install the operating system from an external drive. If you still have problems with the installation, you can try installing the operating system from an external drive.
10. Run Disk Utility once your Mac is updated. When you have finally installed and run the software, we recommend that you run Disk Utility to correct any problems that might have caused the problem in the first place.

What to do if macOS could not be installed on your Mac

If you start up your Mac and see the message MacOS could not be installed on your computer, you will be confused.

To solve this, you should try to quit the installer. Click on the installer window and from the menu above select Quit MacOS installer (or hold down Command + Q). If when you restart your Mac again, you have the same problem with it opening the installer, follow the steps bellow:

1. Start in Safe Mode. Press the shift key while your Mac starts up. The computer will start in safe mode. In Safe Mode, you will see that your Mac doesn’t have all its functionalities, but it will be enough to fix the problem.
2. Once in Safe Mode, open the Mac App Store and search for Mojave.
3. Click on download and wait while the Mojave installer downloads in the background.
4. Once the installer is downloaded, you are ready to install. Now you can continue with the installation.

It’s also possible that you cannot install macOS on your computer because your Mac is too old. You can ask us to know if that is your case. Contact us by phone 933 900 524, by filling out the form in the «Contact» section, or by visiting our repair centre in Barcelona during office hours.

También es posible que macOS no se pueda instalar en tu Mac porque tu Mac es demasiado antiguo. Consúltanos y sal de dudas, puedes contactar con nosotros llamando al 933 900 524, cumplimentando el formulario de la sección “Contacto” o acercarte a nuestro taller en Barcelona en horario de trabajo.