Why can't i install Mac update?

There are a few common reasons why you may be unable to install a Mac update:

Table of Contents

The Update Failed to Download or Install

If your Mac fails to download an update from the App Store or the update fails to install, there are a few things you can try:

Check your internet connection – Make sure you have a stable, fast internet connection when downloading updates. Slow speeds can cause the download to fail.

Restart your Mac – Try restarting your Mac before attempting to download or install the update again. This can clear out any software issues.
Free up storage space – Make sure you have sufficient storage available on your Mac. Large updates may fail to download or install if you have insufficient disk space.
Use wired ethernet – Downloading over WiFi can sometimes result in errors. Try using a wired ethernet connection for faster, more reliable downloads.

Check App Store settings – Open the App Store preferences and make sure automatic downloads and updates are enabled.
Try again later – Server issues can prevent updates from downloading. Try again in a few hours if the download fails multiple times.

If an update fails to install, restart your Mac and try installing it again. This will often resolve random errors that occur during installation.

Your Software is Too Out of Date

In some cases, your Mac may be so outdated that it cannot directly install the latest updates. For example, if you are running OS X 10.8 Mountain Lion and try to install a macOS 10.15 Catalina update, it will fail because there are several major updates in between that must be installed first.

Check to see if your Mac is more than 2-3 major OS versions behind. If so, you will likely need to do the following:

Update to the latest compatible OS your computer supports – Find the latest OS your Mac can run by checking Apple’s compatibility charts or running the compatibility checker.

Once updated, install available updates for that OS version.
Repeat steps 1 and 2 until your Mac is on a recent enough OS to install the latest updates.

This gradual install process may take some time, but is necessary when your OS is significantly outdated and incompatible with the latest updates.

Problems with the macOS Installer

Corruption or issues with the macOS installer application can also prevent successful installation of updates. If you are trying to install a major macOS version upgrade like Big Sur and it fails during installation, try the following:

Re-download the installer – Delete the installer app from your Applications folder and re-download it from the App Store.
Try a different install method – Use a bootable USB installer drive instead of installing directly from the app.

Boot into Safe Mode – Install the update while booted into Safe Mode as this disables certain software.
Reset NVRAM – Reset your Mac’s NVRAM as corrupt settings may affect installation.
Perform a clean install – Back up your data and do a clean macOS install, then migrate your data.

A clean install is most likely to fully resolve any issues with the installer app, but try the other methods first if you want to avoid a clean install.

Third Party Apps Are Incompatible

Updates can sometimes fail to install due to incompatibilities with third party apps, particularly older apps. Problems could occur during either the download or installation phase.

If you suspect a third party app is causing problems:

Check for app updates – Install any available updates for your apps.
Disable login items – Temporarily disable any non-essential apps that load automatically at login.
Boot into Safe Mode – Download and install the update while booted into Safe Mode.

Remove problematic apps – As a last resort, delete and re-install third party apps that may be causing conflicts.

Be sure to check the developer’s website for information on compatibility with the latest version of macOS before removing any apps as they may have an update available.

How to Fix macOS Update Stuck at Verifying

If your Mac gets stuck verifying the update download or verifying the update after restarting, try these fixes:

Allow the verification process several hours to complete. It can take time.
Check internet connectivity and retry.
Restart your Mac and try the verification again.

Reset NVRAM on your Mac.
Download the update again and re-verify.
Use Safe Mode to install the update.

In most cases, restarting your Mac or retrying the verification after a period of time will allow it to complete. If you continue to face this issue, using Safe Mode is generally effective at bypassing any problems.

How to Fix Updates Failing to Install on macOS

If a macOS update fails to install, hangs, or displays an error, try the following:

Restart your Mac – This will often resolve intermittent errors.

Free up drive space – Ensure you have at least 10GB of available storage.
Check internet connectivity – Use Ethernet if available for a reliable connection.
Disable security software – Temporarily turn off any antivirus software.

Boot into Safe Mode – Install the update in Safe Mode.
Reset SMC and NVRAM – This can fix firmware and settings issues.
Create a new user account – Install the update while logged into a fresh user account.

Perform a clean install – As a last resort, do a clean install of the OS update.

Starting the install while in Safe Mode is typically very effective at resolving most issues. A clean install should be done if all else fails.

Fix for App Store Spinning Wheel During Update

If you see the spinning wheel in the Mac App Store when trying to download an update, it usually means the download is stuck. Here are some things to try:

Check your internet connection and speed. Ensure you have a strong WiFi or Ethernet connection.
Restart your Mac and try the update download again.
If on a metered connection, disable the “Use cellular data” option in the App Store.

Switch to a different network if possible. Try downloading on a different WiFi network.
Clear the Mac App Store cache and cookies, then retry.
Create a new user account and attempt the download again.

If you continue to see the spinning wheel, your best option is to switch to a different network with a stronger internet connection. Cellular data connections can also cause this issue.

How to Troubleshoot Slow Update Installation

A slow update installation process could indicate a problem. Try the following to speed it up:

Disconnect external devices to prevent interference.

Close all other apps and windows to dedicate system resources.
Restart your Mac before installing the update.
Connect your power adapter to prevent system sleep.

Quit apps that continue running in the background.
Check Activity Monitor for any high CPU or disk usage processes.
Boot into Safe Mode to isolate software issues.

Reset NVRAM and SMC in case that helps improve performance.

If it becomes stuck for an extended time, you may need to restart the install process. A persistently slow update installation can indicate a larger problem.

Fix for Insufficient Storage Error

If you receive an error that your startup disk lacks sufficient space for the update, take the following steps:

Open Storage Management and optimize your storage to free up space.
Reduce the number of files and apps on your startup drive.
Move files to external storage or cloud storage if needed.

Uninstall large apps and games you no longer use.
Store photos/videos on an external drive.
Run OmniDiskSweeper to find and remove large unused files.

Enable optimized storage for your Photos library.
Check for old system and app files that can safely be deleted.
As a last resort, upgrade to a larger startup disk.

Apple recommends at least 10GB of available storage for major macOS version updates. Freeing up disk space should resolve the error and allow the update to install.

Fix for macOS Already Installed Error

If you try to reinstall or upgrade macOS and get a message that the version is already installed, try these fixes:

Restart your Mac and check About This Mac to confirm the version.

Use Recovery Mode to reinstall the macOS over the existing installation.
Erase the startup drive then do a clean install of the desired version.
Review your install log at /var/log/install.log for clues.

Reset NVRAM and SMC in case this corrects false version detection.
Contact Apple support for additional assistance if needed.

In most cases, restarting and reinstalling the same version of macOS will resolve this error. Erasing the startup drive is required if you want to do a totally clean OS install.

How to Fix macOS Update Failed Error

If you receive a generic “Update Failed” error when trying to install a macOS update, try the following:

Check Apple’s update status page for any known issues.
Restart your Mac and try installing the update again.

Use Activity Monitor to watch for processes causing high CPU/disk usage.
Check system logs at /var/log/install.log for failure reasons.
Make sure your date & time settings are correct.

Create a new admin user account and install the update while logged in there.
Reset your Mac’s NVRAM and SMC controller.
Do a clean install of macOS from Recovery Mode or a bootable USB.

Creating a new user account and trying the update often resolves general failures. Resetting NVRAM and performing a clean OS install are good troubleshooting steps as well.

Conclusion

Troubleshooting Mac update installation issues involves steps like checking for proper OS compatibility, freeing up disk space, resolving third party app conflicts, verifying system file integrity, and isolating software issues. For advanced troubleshooting, resetting NVRAM and SMC, booting into Safe Mode, and performing a clean install are effective techniques. Checking Apple Support and community forums for related issues can also help diagnose more stubborn update problems. Backing up your data before making system modifications allows for smoother recovery. With consistent effort and patience, you can typically resolve Mac update installation failures and keep your system up-to-date.