Restoring or reinstalling the macOS operating system on your Mac without an internet connection can be challenging, but is possible with some preparation and the right steps. The process involves downloading the macOS installer beforehand, creating a bootable USB installer drive, booting from that drive, erasing your Mac’s disk, and then reinstalling the operating system. This guide will provide an overview of the necessary steps to reinstall macOS Monterey or later without an internet connection.
Back Up Your Data
Before reinstalling macOS, it is critically important to back up your data. A backup protects you against data loss in case anything goes wrong during the reinstallation process. According to Apple Support, “Use a backup to restore your files, even after the original files are deleted from your Mac.” (https://support.apple.com/mac-backup)
There are a few options for backing up your Mac’s data. The easiest is to use Time Machine, Apple’s built-in backup software. Time Machine can back up your entire Mac to an external hard drive or Apple’s iCloud service. To start a manual backup with Time Machine, click the Time Machine icon in the menu bar and select “Back Up Now.” (https://support.apple.com/guide/mac-mini/back-up-and-restore-apdc6980d3be/mac)
You can also manually backup your files by copying them to an external hard drive, cloud storage service, or external SSD. Be sure to backup any important documents, photos, music, or other media files before reinstalling macOS.
Taking the time to properly back up your data before reinstallation can save you from catastrophe if anything goes wrong or data is lost during the process. Protect yourself by taking recent backups of all your important files.
Download macOS Installer
Since your Mac does not have an internet connection, you will need to download the macOS Monterey installer on a separate device that has access to the internet. The easiest way is to download the installer on another Mac that is connected to the internet.
To download the macOS Monterey installer on another Mac:
- Go to the App Store on the Mac with internet access.
- Search for “macOS Monterey” and click “Get” to download the installer.
- Once the download is complete, locate the installer file in your Applications folder. It will be called “Install macOS Monterey.app”.
Alternatively, you can download the installer on a Windows PC and create a bootable USB from there. Here are direct links to download the macOS Monterey installer from Apple’s servers:
https://mrmacintosh.com/macos-12-monterey-full-installer-database-download-directly-from-apple/
https://osxdaily.com/download-macos-monterey-12-full-installer/
Once downloaded, the installer will need to be transferred to a USB flash drive to create bootable installation media, which is covered in the next section.
Create macOS Installer USB
The next step is to create a bootable macOS installer on a USB drive. This will allow you to install macOS on your Mac from the USB drive. Here are the steps:
First, you’ll need a USB flash drive that is at least 16GB in capacity. The flash drive will be erased, so make sure there is no important data on it. Connect the USB drive to your Mac.
Next, launch Terminal, which you can find in /Applications/Utilities/. In Terminal, type the following command and press return. Replace “MyVolumeName” with the name of your USB drive. This will erase and format the drive:
diskutil eraseDisk JHFS+ MyVolumeName MBRFormat /dev/disk2
With your USB drive formatted and ready, now type the following command in Terminal to create the bootable installer, replacing “Install macOS Monterey.app” with the name of your installer app:
sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolumeName -- /Applications/Install\ macOS\ Monterey.app
This will take some time as it copies the installer files over. After it finishes, you’ll have a bootable USB installer ready for installing macOS 1.
Boot From the Installer USB
Once you have created the bootable USB installer, the next step is to boot your Mac from the USB drive instead of the normal startup disk. To do this:
1. Insert the USB installer into your Mac.
2. Reboot your Mac and immediately hold down the Option (or Alt) key on your keyboard. Keep holding the key down until you see the startup manager screen.
3. Use the arrow keys to select the USB installer drive, which will be labeled something like “Install macOS Monterey”.
4. Press Return or Enter to boot from the selected drive.
Your Mac will then start up from the USB installer instead of your normal startup drive. Once booted, you can proceed with erasing your Mac’s disk and reinstalling macOS.[1]
[1] How to Boot from USB? – Windows, Mac, Linux
Erase Your Mac’s Disk
Before reinstalling macOS, you’ll need to erase your Mac’s disk to remove any existing files, applications, and settings. To do this, you’ll use Disk Utility which is included in the macOS Recovery mode.
Follow these steps to erase your disk (Apple Support):
- Boot into Recovery mode by holding Command + R when restarting your Mac.
- When the macOS Utilities screen appears, select Disk Utility and click Continue.
- In Disk Utility, select your Mac’s disk from the sidebar.
- Click the Erase button in the toolbar.
- Enter a name for the disk, select a format (APFS is recommended), and click Erase.
This will completely erase all data on the disk, preparing it for a clean install of macOS.
Reinstall macOS
Now it’s time to actually reinstall the macOS operating system. Follow these steps:
On the Utilities screen, select “Reinstall macOS” and click Continue. Follow the onscreen prompts to begin the process of reinstalling macOS. Agree to the terms and conditions, choose your disk to install it on, and let the process run – this can take anywhere from 20 minutes to over an hour depending on your machine.
The macOS installer will erase your disk and do a clean install of the operating system you downloaded earlier. Be patient and let the process complete without interrupting it.
Once the installation is finished, your Mac will reboot into the setup assistant. Follow the onscreen instructions to complete setting up your Mac again.
Restore Your Data
Once you have finished reinstalling macOS, the next step is to restore your data from a backup. If you use Time Machine to back up your Mac, you can easily restore all your files, applications, and settings after reinstalling the OS. Time Machine keeps hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for everything older than a month.
To restore from a Time Machine backup after reinstalling macOS (Apple Support):
- Open the Time Machine app on your Mac. It’s located in the Applications folder.
- Select “Enter Time Machine.” Your available backups will show on the right side.
- Browse and find the files/folders you want to restore. Hold the Command key as you click to select multiple items.
- Click the Restore button when you’re ready. Time Machine will copy the files back to your Mac.
This process allows you to selectively restore files, applications, settings, and more from your Time Machine backup. Take your time to grab everything you need. With a little work, you’ll have your Mac set up just like it was before reinstalling.
Reinstall Apps
After reinstalling macOS, you’ll need to reinstall your apps and settings. The easiest way is to reinstall apps you purchased from the Mac App Store. To do this:
1. Open the App Store app on your Mac.
2. Click on your account icon in the bottom left and sign in with your Apple ID.
3. Click on the ‘Purchases’ tab to see a list of all the apps you’ve downloaded previously.
4. Find the app you want to reinstall and click the ‘Install’ button next to it. The app will download and install.
For apps not installed via the App Store, you’ll need to reinstall them from their original source, like a disc or downloaded DMG file. You may need to find the license code to reactivate some apps after reinstalling them. Refer to the app developer’s instructions on how to reinstall their software.1
To restore app settings and data, refer to your backup from the beginning of this process. Apps like browsers and email clients often store settings and data in your user account library folders, which can be restored from the backup.
Conclusion
In summary, reinstalling macOS Monterey without an internet connection involves several key steps. First, back up your data to ensure nothing is lost. Then, download the macOS installer on a separate Mac that has internet access. Next, create a bootable USB installer drive and boot your Mac from it. Once booted into the installer, erase your Mac’s disk and reinstall a fresh copy of macOS. After the installation is complete, restore your data from the backup and reinstall apps as needed. With some preparation and the creation of a bootable installer drive, it is possible to fully reinstall macOS Monterey without an active internet connection. Just be sure to have a backup available to restore your files and settings.
