Step-by-Step Guide: Upgrading Your Mac to macOS 15 Sequoia
Note: macOS Sequoia launches on September 16, 2024. By default, we defer/block upgrades for 60 days (until November 15, 2024) to prevent accidental updates and give your organization time to prepare.
How to Check macOS Compatibility
Before rushing headlong into the upgrade, it’s crucial to confirm that your Mac is supported by the version of macOS you plan to install. This is the difference between a seamless upgrade and an afternoon spent lamenting a “computer not supported” message.
- Consult Your Mac Model: First, determine which Mac model and year you’re running. Click the Apple logo (upper-left corner) > “About This Mac.”
- Check Version Lists: Each macOS release has a specific list of compatible models. You can match your Mac’s model/year against these lists, which are widely published by sources like iMore, MacRumors, and tech support sites like EveryMac.com.
- Third-Party Compatibility Tools: Sites like EveryMac.com and Mactracker (a handy app) also compile regularly updated compatibility matrices if you want quick reference.
- Company Policy: If you’re in an organization, your IT team or account manager can often confirm which Macs are eligible for the newest upgrade cycle.
Double-checking now can save you from headaches later, especially if you’re managing multiple Macs across departments.
Our recommendations:
Stay on the latest macOS version once your apps/services are confirmed compatible.
We defer upgrades by default to reduce disruptions.
Contact your account manager to test upgrades on a pilot machine.
Apple supports only the latest three macOS versions with security updates.
Note: Upgrade as soon as practical after validation to ensure peak performance, security, and access to new features “
Upgrade Your Mac to macOS Sequoia
How to Check Your Current macOS Version
Not sure which version your Mac is running? It’s easy to find out:
- Click the Apple menu () in the upper-left corner of your screen.
- Select About This Mac.
- Your current macOS version (for example, “macOS 14 Sonoma”) will be listed at the top of the window.
Verifying your system’s version helps ensure compatibility before moving forward with the upgrade.
Creating a Bootable Installer (Optional, Advanced)
A bootable installer comes in handy if you’re upgrading several Macs and prefer not to download the installer for each device, or if you’re unable to start your Mac the usual way. This method can also serve as a troubleshooting tool when recovery options aren’t available.
Here’s how to get started:
- Download the macOS installer on a compatible Mac. You can obtain it through the usual app store or directly using a secure download from a trusted IT resource.
- Prepare a USB flash drive (at least 16 GB recommended) and back up its contents.
- Use a reliable tool—such as Terminal commands or a trusted third-party utility like DiskMaker X—to turn the USB drive into a bootable installer by following the step-by-step prompts.
- Once complete, you’ll be able to plug this installer into any compatible Mac, start up while holding the Option (⌥) key, and select the USB drive as your startup disk.
When to use this method:
- Deploying the upgrade across multiple Macs efficiently
- Working around download errors or network restrictions
- Recovering a Mac that won’t boot normally
Note: This is an advanced option—most users will not need to create a bootable installer for day-to-day upgrades.
1 – PREPARATION
Compatibility Check
Before you begin, confirm that your computer meets the system requirements for the specific operating system version you plan to download. Start by reviewing the official compatibility list published by the OS vendor or trusted sources like TechRadar or Tom’s Hardware. If your device model isn’t listed or falls below the minimum hardware specifications, you may encounter issues such as unavailable download options or warnings about incompatibility. Taking this step early can save you the frustration of failed installations or unexpected errors later on.
- Check storage: Ensure at least 49 GB free ( > About This Mac > Storage).Freeing Up Storage Space
If you find you’re short on the required 49 GB, don’t panic—there are a few quick ways to clear up space:Empty the Trash: It sounds obvious, but files linger there taking up precious gigabytes until you say goodbye.
Remove Large Files: Head to your Downloads, Movies, and Documents folders. Move anything you don’t need—think old Zoom recordings, installers, and holiday photos from 2013—to an external drive or cloud storage (Google Drive, Dropbox, Box).
Uninstall Unused Apps: Open your Applications folder and drag anything you haven’t used this year to the Trash. Games and video editors are notorious for hogging space.
Clear Cache and Temporary Files: Apps like CleanMyMac X or DaisyDisk can help identify and zap sneaky system and app cache files hiding in the background.
Move Media to Cloud Services: Consider shifting your photo and music libraries to services like OneDrive or Amazon Photos.
Delete iOS Device Backups: Old phone backups in your system folder can devour space undetected. Remove any you no longer need.Take it step by step, check your available space again, and you’ll be ready for the upgrade in no time. - Back up data: Use Time Machine, Los Angeles IT Backup Manager, or another backup method—confirm it’s up to date.
- Disconnect devices: Unplug everything except power and Ethernet.
- Update system: In MacManage, run Check for Major Updates to prep macOS and apps.
- Restart: Reboot your Mac before beginning the upgrade.
2 – INSTALL VIA MACMANAGE
Before you begin: The upgrade can take up to 2+ hours, during which your Mac will be unusable. Start early in the day (or overnight if convenient). Avoid Fridays, evenings, and weekends.
- Open MacManage from Applications. If you’re an admin, you can also use System Preferences → Software Update.
- Search for Install macOS Sequoia and click Install. Confirm when prompted (the popup may appear behind other windows).
Downloading an OS Installer via the App Marketplace
If you need to download an operating system installer from an app marketplace, follow these best practices to ensure a smooth process:
1. Check Compatibility: Confirm that your device supports the OS version you plan to download. Incompatible devices may not display the option to download or could show error messages.2. Prepare Your Device: Make sure your current system meets any minimum requirements for the new OS.
If you’re creating a bootable installer, verify that your device is running an up-to-date system capable of handling installation files.
3. Access the OS Installer:
– Use the app marketplace or store relevant to your device (e.g., Google Play, Microsoft Store).
– Search for the exact OS version you wish to install. If search results act up, switching browsers—for example, moving from Chrome to Firefox—can sometimes help.Examples:
– Windows 11, Windows 10
– Ubuntu 24.04, Ubuntu 22.04
– Fedora 39, Fedora 38
– Linux Mint 21, Linux Mint 204 Initiate the Download:
– Look for the clear Install or Get button in the marketplace.
– If a prompt appears asking you to confirm, proceed to allow the download to begin.5 After Downloading:
– The installer usually appears in your main applications or downloads folder.
– Either launch the installer immediately and follow the on-screen instructions, or leave it for later—simply quit the setup, and the installer will remain available for future use.Continue with the installation section below.
- The 12 GB installer will download. Close other apps for a smoother process.
- Your Mac will reboot automatically. If FileVault is enabled, enter your password when asked.
- Follow on-screen prompts, log in when required, and allow the progress bar to complete.
Using a Bootable Installer for Multiple Macs
If you’re planning to upgrade several Macs and want to avoid repeated downloads, a bootable installer is a smart choice. This approach is also helpful if you can’t use standard upgrade methods like macOS Recovery.
Follow these steps:
- Get the Installer: Download the latest macOS installer on a compatible Mac. Use MacManage, a reliable third-party source, or your organization’s preferred tool.
- Create the Bootable Drive: Plug in a USB drive (at least 16 GB), then use a tool like DiskMaker X or Terminal to turn it into a bootable installer. Double-check the process has completed before continuing.
- Install macOS with the Bootable Drive:
– Insert the USB drive into the target Mac.
– Restart the Mac while holding the Option (⌥) key to select the bootable installer from the Startup Manager.
– Choose “Install macOS” and follow the on-screen prompts to upgrade.
Tips:
- Repeat for each Mac, but disconnect the installer drive as soon as installation begins.
- Always back up important data first and verify application compatibility.
This method can greatly simplify bulk upgrades in busy offices or when internet connections are limited.
3 – CLEANUP
- After the Mac restarts, log in as usual.
- Run Check for Major Updates in MacManage to ensure macOS and Microsoft apps are fully updated.
- Open your business-critical apps to confirm they work properly; some may require system extension approval.
- If you encounter issues or have questions, contact your IT team or Los Angeles IT support.
- What to Do If Your Computer Fails to Start Up? If your computer doesn’t fully start up during or after installation, don’t panic. Instead, follow these steps to get back on track:- Restart the computer and listen for any unusual startup sounds.
– Try booting into your recovery environment (your IT team can guide you if you’re unsure how).
– If the regular method isn’t working, you might need to reinstall your operating system using the recovery options available.
– For persistent issues, reach out to your IT team or our Los Angeles IT support—especially if your device is crucial for daily work.Getting stuck happens, but with these steps, you’re on the path to a smooth restart.
Reinstalling the Operating System When Your Mac Won’t Start
If your Mac refuses to boot up properly, or updates aren’t going through, you still have options—even if things look dire.
Boot from macOS Recovery:
You can use the built-in Recovery mode to reinstall macOS. Here’s how:
- Shut down your Mac completely.
- Hold down the appropriate recovery key combination (often Command + R) while turning the Mac back on.
- Release the keys when you see the Recovery window.
- Follow the on-screen instructions to reinstall macOS.
This approach lets you start fresh without requiring a working operating system on your Mac.
If you run into trouble or your recovery tools aren’t working, don’t hesitate to reach out to your IT department or Los Angeles IT support for hands-on help.
Using Recovery Options to Reinstall the Operating System
If your Mac refuses to boot normally, or you’re unable to install updates as expected, you can fall back on the built-in recovery tools to perform a fresh installation of macOS.
- Start by shutting down your Mac completely.
- Hold down the appropriate key combination (usually Command + R) as you power it on. Keep holding until you see a loading screen with a utilities menu.
- In the utilities menu, select “Reinstall macOS” and follow the on-screen prompts.
This process walks you through downloading and reinstalling the operating system—perfect for stubborn update issues or if your Mac just won’t cooperate. Be patient, as it can take some time depending on your internet connection.
Once reinstallation finishes, your Mac will restart—then you can resume the steps above to check for updates and make sure your essential apps are behaving.
What if My Mac Says It’s Already Up to Date?
If you check for updates and see a message that your Mac is up to date, don’t panic—this means there are no newer updates currently available for your specific model.
- If you were expecting to see the macOS Sequoia upgrade but it isn’t listed, your Mac may not yet be eligible, or the upgrade has not been released to your device by your organization.
- Sometimes, upgrade availability can vary by device compatibility or by company policy.
If you have questions or believe your device should be eligible, reach out to your IT team or Los Angeles IT support for assistance—they can let you know if there’s a rollout delay or if further action is needed on your end.
Need more details on downloading files?
If you’d like additional guidance on downloading files with your web browser, comprehensive instructions are available from resources like Mozilla Firefox Support and Google Chrome Help Center. These step-by-step guides cover everything from saving attachments to managing your downloads folder, making it easy to find what you need—no matter which browser you prefer.
Installing an Older Disk Image (.dmg) File
- Check Compatibility First: Make sure the Mac you’re using supports the older operating system version you plan to install. Not all Macs can run all versions, so a quick compatibility check saves you time and trouble.
- Download the Disk Image: Look for a reliable download source for the version you need. It’s often best to use a trusted browser such as Firefox or Chrome if you encounter any hiccups during the download process.
- Examples of older versions include Sierra, El Capitan, Yosemite, Mountain Lion, and Lion.
- Locate Your Download: By default, most browsers place downloaded files in the Downloads folder. You can access it from the Dock or via the Finder sidebar. Your disk image should appear as a file ending in .
- Open the Disk Image: Double-click the file to mount it. This action opens a new window displaying the contents, usually a package file with a extension.
- Install the Package: Next, double-click the file found within the mounted image. Follow the prompts on your screen—these typically guide you through installing the software into your Applications folder.
- Finish Up Installation: Once installation is complete, locate the installer within your Applications folder and double-click it to begin setting up the operating system itself. Follow all on-screen steps to complete the process.
If you hit any bumps along the way or need assistance, don’t hesitate to reach out to your IT support team in Los Angeles.
