An Error Occurred While Preparing the Installation

Installing macOS is often a straightforward process. However, the process can sometimes be delayed when you receive a notification that reads, “An error occurred while preparing the installation.”

Before we start:

Mac software updates not working can be a huge inconvenience, especially if you’re unsure how to proceed. Fortunately, you don’t have to figure it out alone. MacKeeper’s Premium Services exist for this very reason—to identify and solve your Apple computer’s basic issues that can lead to you receiving an installation-related macOS error message.

Harness MacKeeper’s Premium Services solution to remove the macOS installation error. Here's how:

1. Download the MacKeeper app on your Mac, open it, and choose Premium Services from the sidebar.
2. Navigate to the right side of the screen, locate the blue Chat Now button, and click on it.
3. Describe the error you’ve received and follow the tech expert’s instructions.
4. Sit back and let MacKeeper’s technician resolve the issue, so you can proceed to install macOS.

Similar to your Mac getting stuck checking for updates, encountering an error while installing macOS is common. More importantly, you can fix it. In this article, we’ll show you various methods to remove the error message. Let’s get started.

What “an error occurred while preparing the installation” means

You might receive “an error occurred while preparing the installation” message when updating your device, which means that your MacBook failed to complete the update. This can happen because of an unstable internet connection, incorrect time and date settings, or possible issues with Apple’s servers.

Important: 

Big Sur users commonly suffer from “you don’t have permission to open the application” error due to network connection issues. Check it out before proceeding further.

What causes the “an error occurred while preparing the installation” issue?

There are several reasons why you’ve received the “an error occurred while preparing the installation” issue: date and time mismatches (especially if you haven’t selected Apple as the source for your date and time), corrupted installation media, or problems with the Mac hardware, like when select the disk where to install macOS is blank.

How to fix an error that occurred while preparing the installation of macOS

Here’s how to rectify the error that comes up while preparing a macOS installation:

1. Check device compatibility.
2. Restart your Mac.
3. Advance in stable Internet connection.
4. Check and correct date and time settings.
5. Check disk health using Disk Utility.
6. Ensure adequate free space on your Mac.
7. Reset NVRAM/PRAM.
8. Boot your Mac into Safe Mode.
9. Try macOS Recovery.
10. Erase your drive and reinstall macOS.
11. Get a different macOS installer.
12. Update Mac firmware before installation.
13. Contact Apple support for professional assistance.

Let’s explore the 13 methods you can implement to remove the error relating to preparing a macOS installation.

1. Check device compatibility

While some Mac users might be eager to install the latest macOS version, it might not be compatible with their specific Mac model. We started by checking if our device was compatible with the macOS release we were attempting to install, whether it was OS X Big Sur, El Capitan, Catalina, Mojave, Monterey, Sierra, Big Sur, or Ventura. We recommend you do the same. You can find the compatible device list for your desired macOS version on the Apple Support site.

2. Restart your Mac

We’ve often found that a simple restart refreshes the Mac system and corrects minor issues, such as macOS installation errors.

Restart your MacBook to see if the problem persists. Take these steps to do it:

1. Click on the Apple menu in the top-left corner of your computer and select the Restart option.
2. Wait for your computer to restart and try to reinstall the macOS again.

3. Advance in stable internet connection

Often, we’ve found that the minor issues we’ve experienced can be traced to an unstable internet connection, which can interfere with a macOS installation. Test your internet connection by visiting websites, streaming video content, or using a few apps. If you don’t encounter any problems, you can rule out your internet connection as the culprit.

4. Check and correct date and time settings

Having the wrong time and date set on your Mac can surprisingly affect your ability to install macOS. Follow our hints below to review your laptop’s time and date settings:

1. Open System Settings/Preferences from the Apple menu and click General > Date & Time.
2. Check if your time is correct, enable the option to Set Time and Date Automatically, and select Apple as the source.

5. Check disk health using Disk Utility

Disk errors can prevent the operating system from accurately reading, writing, and partitioning the drive, thereby interfering with the installation process.

Follow these steps to check your Mac’s disk health:

1. Open Applications > Utilities > Disk Utility or bring it up using Mac’s Spotlight search.
2. Choose the target disk you want to check, click on the Info button in the upper-right corner of the window, and review the report to assess its health.

A tip from the MacKeeper team: 

If the disk is impaired, we advise you to repair the disk with Disk Utility.

6. Ensure adequate free space on your Mac

Insufficient storage prevents your device from copying installation data and creating the necessary temporary files. In this situation, we freed up space to prepare for a macOS installation.

Here’s how to check your Mac’s storage:

1. In System Settings, click on General > Storage > All Volumes.
2. Review how much storage you’ve used up and how much is available.

7. Reset NVRAM/PRAM

NVRAM and PRAM store system settings. Therefore, issues related to NVRAM and PRAM, such as boot preferences, can lead to macOS installation failures. We recommend that you reset NVRAM/PRAM on your Mac to resolve this.

8. Boot your Mac into Safe Mode

Mac’s Safe Mode reduces third-party app conflicts by only running Mac’s essential services, which can help resolve the macOS installation error.

Find out how to boot your MacBook into Safe Mode below:

1. For Macs with Apple Silicon: Turn off your computer and hold down the power button until the Loading startup options page appears on the screen. Select the boot disk, hold down the Shift key, and click Continue in Safe Mode. You’ll notice Safe Boot in the menu bar after your Mac restarts.
2. For Intel-based Macs: Restart your laptop by holding down the Shift key, followed by the power button. Just let go of the Shift key when the login window appears. Note that you may be asked to log in again. After your computer has successfully restarted, you’ll see Safe Boot in the menu bar.

9. Try macOS Recovery

Mac’s Recovery Mode can help fix a damaged disk or correct your device’s time and date settings, which could remove the installation error you’ve received.

Here’s the process we followed to enter Mac’s Recovery Mode:

1. Restart your Mac via the Apple menu and immediately hold down the Command + R keys until the Apple logo or spinning globe appears on the screen.
2. After entering the macOS Utilities window, click on Reinstall macOS > Continue and follow the prompts to complete the process.

10. Erase your drive and reinstall macOS

When all else fails, you can try erasing the drive. However, we recommend you only consider this option as a last resort. Erasing your drive and reinstalling macOS allows you to install the operating system you want.

To erase your drive and reinstall macOS, do this:

1. Restart your device and immediately press the Option + Command + R keys. Release them when the Apple logo appears on your screen.
2. Wait for the macOS Utilities window to appear, and then click on Reinstall macOS > Continue.
3. Follow the on-screen instructions to complete the macOS installation.

11. Get a different macOS installer

If the bootable disk is the problem, using a different one could do the trick. We opted to install macOS via the App Store.

Here’s how to install macOS from the App Store:

1. Open the App Store on your MacBook Pro, Air, or iMac device, type the macOS version you want to install in the search bar, and press Enter.
2. Find the macOS version from the results, click on View > Get, and follow the prompts to complete the installation process as you’ve done in the past.

12. Update Mac firmware before installation

Outdated firmware lacks support for new system features and may not be compatible with your hardware. Firmware updates are implemented during macOS installation, so ensure you have the latest macOS version compatible with your computer.

13. Contact Apple support for professional assistance

If you’re still out of luck after trying all the steps outlined in this article, it may be time to rope in an expert. Contact Apple Support to get help.

A note from our experts: 

While Apple Support is an option, it doesn’t provide dedicated assistance. That’s what you get when you contact an expert technician through MacKeeper's Premium Services. Our app assigns you one of more than 150 experts that are available 24/7 to help resolve common Apple issues remotely.

Why not give it a try? Leverage MacKeeper’s Premium Services to address your macOS installation error. Here’s how:

1. Download and install MacKeeper on your Mac.
2. In the MacKeeper app, select Premium Services from the sidebar, followed by the Chat Now button on the right.
3. Explain your situation in the chat box and let MacKeeper’s technician take care of it.

Fix the error message that appears when installing macOS

Mac’s “an error occurred while preparing the installation” message is typically a simple issue that can be easily resolved. Use the tips in this helpful guide to get rid of it and proceed with the macOS installation. Remember, MacKeeper’s Premium Services tool is available 24/7 if you run into Mac-related issues, like removing the error message, and require expert help.