Why can't I update my Mac? How do I fix it and upgrade to the latest macOS Big Sur?

Don't worry if you can't update your Mac, Apple Software Update isn't working, or the latest macOS update, Big Sur, won't install on your Mac. On this page, we'll go through all the possible reasons and provide solutions to fix these issues and guide you through successfully updating to the latest macOS version.

Let's start here.

Regarding macOS updates

By default, macOS or Mac OS X is set to automatically check for and download software updates weekly. When an update is available, a notification appears, alerting all Mac users.

However, if you can't use Apple Software Update on your Mac, you can download and install the latest macOS updates manually with these steps:

Manually download the update. Download standalone installers for updates from Apple. Reset your Mac or reinstall the operating system, and so on.

Why can't I update my Mac?

Many Mac users report that they're unsure why they can't find software updates or why a downloaded macOS update won't install on their Mac. Let's look at some reasons why you might not be able to install the latest macOS update:

Reason:

• Apple Software Update fails
• Unstable internet connection
• Lack of storage space for the latest macOS update
• The Mac is too old to update
• The Mac doesn't detect or show any new updates available

Symptoms:

Regardless of the reason, here are some symptoms you might see on your Mac. If you experience any of them, proceed to the next section and fix the issue right away:

• Your Mac might freeze during a macOS update download or install.
• The download for a new macOS update is taking too long: Downloading macOS...
• Error message 1: The macOS installer could not continue
• Error message 2: An error occurred while installing the selected updates.
• Error message 3: There isn't enough space on the selected volume to update the operating system.

How to fix the “Unable to Update Mac to the Latest macOS Big Sur” Error? All Solutions are Here

When macOS updates, the installer, or even a reset of macOS fails to work on your Mac, do you know what to do? Try the solutions in this section to fix the “can't update Mac” error and get the latest macOS version, Big Sur, installed on your computer right away.

Method 1: Check Your Network Connection and Restart Your Mac

Applies to: Long download times

When your Mac gets stuck on the “Downloading macOS…” message, an unstable internet connection is the most common reason behind this error.

How to fix it:

Step 1: Close the macOS Downloads window.

Step 2: Disconnect your Mac from Wi-Fi.

Step 3: Restart your router.

Step 4: Reconnect your Mac and other devices to the Wi-Fi network.

Make sure that your Mac and any other devices you're using are connected to the Wi-Fi network and working properly.

Step 5: Try running the new software update.

Go to the Apple menu > choose “System Preferences” > click “Software Update” > wait for your Mac to check for new updates > click “Update Now.”

If Software Update doesn't find any new updates, or if the update fails, try the next solution for help.

Solution 2: Update your Mac to the latest version of macOS manually

Applies to: Failed Apple software updates, "macOS Install Cannot Complete" error.

How to fix it:

Step 1. Turn off your router and turn it back on.

Step 2: Make sure your Mac is connected to Wi-Fi properly.

Step 3: Turn your Mac off, then turn it back on.

Step 4. Close all apps on your Mac.

Step 5: Try updating your Mac manually again:

Click the Apple menu and select “System Preferences.” Click “Software Update,” let your Mac check for new updates, click each one to apply it, and then click “Install Now” or “Install [X] Updates.”

Solution 3: Try updating manually (by downloading the update from the Apple website)

Applies to: Install failed - "An error occurred while installing the selected updates."

If your Mac isn't finding new updates through Apple Software Update, you can try downloading the latest updates directly from the Apple website.

How to resolve it:

Step 1: Go to the Apple Support Downloads website:

The Chinese link for https://support.apple.com/downloads is: https://support.apple.com/zh-cn/downloads

Step 2: Choose which updates to install.

Step 3: Download and install the update.

Follow the onscreen instructions to install macOS on your Mac.

Step 4: Wait for the update to install, then restart your Mac.

Fix 4: Clean up your Mac's disk and re-download/install macOS updates

Applies to: "There is not enough space on the selected volume to update the operating system."

How to fix it:

Step 1: Free up Mac disk space by deleting cache files and other large files.

Note: If you have large files, it's a good idea to keep them on an external hard drive. (You'll need 10 GB of free space.)

When you accidentally delete files, a reliable file recovery software for Mac comes to help.

Step 2: Continue to check for new updates using Software Update.

Or click Install to continue with the Mac update you downloaded.

If Software Update fails, go to the Apple Download website to download the latest update manually.

How to Update/Reinstall macOS Without Losing Data

This page covers the complete process of updating and installing the latest macOS Big Sur, Catalina, Mojave, etc., without losing any data. Follow this guide to install the macOS version you want on your computer right now.

Fix 5: Reset your Mac and check for new updates

Applies to: Mac too old to update, can't find an update - "The requested macOS version is not available."

How to fix it:

Step 1: Restart your Mac and hold down Command + R, Option+Command+R, or Shift+Option+Command+R.

Step 2: When you see the Apple logo, let go of the buttons. In Recovery Mode, choose Disk Utility.

Step 3: Click “Erase” > select your Mac's startup disk, then click “Erase.”

Note that this will remove important files from your Mac. Make sure to back up all important files beforehand. Otherwise, your last resort for Data Recovery would be to use the recommended Mac File Recovery software at the end of this page.

Step 4: Choose Quit Disk Utility. In the next window, choose Install macOS.

Step 5: Follow the onscreen instructions to install macOS on your computer.

Step 6: When the macOS installation is complete, restart your Mac.

Step 7: Run Software Update to check for new macOS updates. Alternatively, visit the Apple Download website to download and install any available updates.

Extra Tip: Recover Lost Files After macOS Update

If you're missing files or data on your Mac after installing a new update, don't panic. You can first check to see if you have a backup.

If you do, congratulations: you can simply restore the lost files from your backup.

If not, stop using your Mac immediately and seek help from a reliable Mac file recovery tool, such as Data Recovery Wizard for Mac.

Step 1: Select the scan location

Launch the Mac Data Recovery Wizard, select the hard drive, SSD, SD card, USB flash drive, or TF card from which you lost your data, and click "Start to Find Lost Files" to begin scanning.

Note: Before data recovery, it's recommended that you back up your Mac from the left sidebar to guard against further data loss. After the backup, the software can recover data from the Mac backup, and your computer can write new data again.

Select the location, then click "Search Lost Files".

Step 2. Filter Lost Mac Data

The software will automatically scan for lost data on your MacBook or iMac. After the scan is complete, you can filter the required data using the "Type" and "Path" buttons.

Step 3: Recover Lost Data or Files

Double-click the file to preview it. Then, click “Recover” to restore the lost data to another location.

"The update couldn't be installed on this Mac" error is fixed, and you can now install the latest macOS right away.

On this page, we explain the causes and symptoms of the "Unable to Update Mac" issue to help you identify the problem.

If you can't download new updates on your Mac, don't worry. Back up all your Mac files to an external hard drive, and work through these solutions one by one. You'll surely overcome the issue and install the latest macOS update, such as Big Sur, on your computer.

For lost files, you can restore them from a backup or use Mac file recovery software.