MacOS Installation Couldn't Be Completed [macOS Sequoia]

Many Mac users reported that they had encountered several errors when the new macOS was released and used to install it. macOS installation couldn't be completed, which is one of the common cases you may encounter, and it is surely annoying. But feel at ease; this post from EaseUS will help you solve this issue and recover lost files during the update.

First Thing to Do: Recover Lost Files During macOS Installation Failure

There is a chance that your critical files will be lost during this macOS installation error if something is wrong with your memory or internal disk. In this case, you can first try restoring your data from Mac Trash; if it doesn't work, then try EaseUS Data Recovery Wizard for Mac.

This Mac data recovery software helps you recover deleted files from your external hard drives on Mac and can also retrieve your missing data when your SD card is not mounting on Mac, and you find data loss on your SD card. 

Here is what you can do to recover your lost files from an external hard drive on Mac:

Step 1. Search for lost files

Correctly connect your external hard drive to your Mac. Launch EaseUS Data Recovery Wizard for Mac, and select the external hard drive. Then, click "Search for lost files" to find lost/deleted files on your external devices.

Step 2. Filter and find lost files

After the scan, all file types will be presented in the left panel. Select the file type to find wanted files on your external devices.

Step 3. Preview and recover

Click the file and preview it. Then, select the files you want to recover and click the "Recover" button. You can save your data to local and cloud drives.

You are welcomed to share this post to social media like Reddit or Linkedin to help more users facing the same Mac installation error:

Ensure Your Mac Is Set to the Correct Time and Date to Fix macOS Installation Failed

If you have accepted this macOS failed to be installed error, it is highly likely that you have set the date and time wrong. Here are the detailed steps you can follow to correct the date and time:

Step 1. Navigate to System Preferences and then locate "Date & Time".

Step 2. Tap on the Padlock and enter your password if needed.

Step 3. Then, choose the "Set date and time automatically" option to correct the date and time.

Reinstall macOS in Recovery Mode to Solve macOS Installation Can't Complete

You may also try reinstalling macOS in recovery mode if the updating you applied is failing. You can do as follows:

Step 1. Restart your Mac and hold the Option + Command + R keys simultaneously.

Step 2. Hold these keys until you see an Apple logo and hard the startup sound.

Step 3. Now, you can reinstall the newest version of macOS by tapping on the Reinstall macOS option.

Here's another way to reinstall macOS. You can create a bootable installer with a USB on the Mac with the help of EaseUS Data Recovery Wizard for Mac. It has a free feature that can create a macOS installer with one click. Check the following guide and have a try:

✨Step 1. Connect USB Flash Drive and Choose a macOS Version

Launch EaseUS recovery software, and choose "macOS Installer" from the Advanced Features. Insert a USB that has more than 16GB of free storage space.

• Option 1: Choose a macOS version you want to install, and a new windows will ask you to download macOS installer from App Store. After downloading the installer, click "Refresh".
• Option 2: If you have already downloaded macOS installer, choose "Add" and select the installer you have downloaded.

Finally, you can choose "Create macOS Installer" to start creating the bootable installer. You can select various macOS versions like macOS Sequoia, Sonoma, Ventura, Monterey, Big Sur, and older versions.

✨Step 2. Erase the USB and Create a macOS Installer

A notice window will appear to warn you this operation will remove everything on this USB. Make sure you have backed up data and nothing important is left on this USB, click the "Erase and create".

✨Step 3. Wait and Check How to Use macOS Installer

The software will automatically format the USB and download macOS installer files. After creating the bootable macOS installer, click the blue link on the interface to learn how to use the macOS Installer boot device to install macOS. Finally, click "Finish" to complete the whole process.

Perform First-Aid on Startup Disk to Fix macOS Installation Can't Be Completed

You may get this macOS installation error because there is a disk permission error in your startup disk. In this case, you can use First Aid on your startup disk like this:

Step 1. Navigate to Applications > Utilities > Disk Utility.

Step 2. When the window appears, choose your Macintosh HD and click First Aid from the top-right menu.

Step 3. Then Disk Utility will automatically check and repair your disk error.

Reset the PRAM and NVRAM Settings to Solve macOS Installation Cannot Be Completed

If there is something wrong with your memory, you may try resetting PRAM and NVRAM without destroying your personal data. Here is how you can do this:

Step 1. Restart your Mac by holding simultaneously the Option + Command + P + R keys

Step 2. Keep holding these keys until you see the second Apple logo or when you hear the starting sound a second time.

Final Words 

This post from EaseUS has looked at how you can solve this macOS installation couldn't be completed error. You can fix this installation failure by changing your Date and Time settings, reinstalling your macOS in Recovery Mode, utilizing First Aid in Disk Utility, and resetting the PRAM or NVRAM settings. If you have accidentally lost your data, use EaseUS Data Recovery Wizard for Mac to help.

FAQs on macOS Installation Couldn't Be Completed

Here are some frequently asked questions that you may be interested in:

1. How do you fix the operation could not be completed on Mac?

• You can try the following method:
• Restart your PC
• Clear the Cache and Cookies
• Update macOS
• Uninstall unused APPs

2. Why is my computer saying macOS could not be installed?

These kinds of messages might have a variety of causes, and occasionally they are transient. Please try the suggested solution, such as downloading the installer again and trying again, if it is provided in the message.