OS X updates come through the Mac's built-in update tools, while a major upgrade may need a compatible installer from Apple. Start with Apple menu > About This Mac to check which version it's running and which update tool to use.
Modern macOS uses Software Update in System Settings. Older OS X machines use App Store Updates or an official older installer. An up-to-date message can mean your Mac is already running the newest version its hardware supports.
Match the update route to the installed version
Note the operating system name, version and Mac model from About This Mac. Include the model year when checking an upgrade. The name MacBook Pro alone doesn't tell you which releases it can run.
An update adds patches within a release; an upgrade changes the major release. A fully patched older system can still need a separate installer for the major upgrade you want.
Apple recommends Software Update in its macOS update instructions because it checks compatibility for you. Start there when the computer has it before picking a version by name.
Back up before installing. Connect your Time Machine disk and let the backup finish, or confirm that your important files have another current copy. Keep the MacBook connected to power throughout installation.
That preparation matters more on an old OS X machine with years of saved files. I'd check the backup before starting a major upgrade, particularly when the Mac is your only copy of those files.
Use Software Update on a modern Mac
For Ventura 13 and newer macOS releases, open Apple menu > System Settings > General > Software Update. Once the search finishes, read the version it offers.
On macOS Mojave 10.14 through Monterey 12, use Apple menu > System Preferences > Software Update. That's why newer instructions can point to a button your Mac doesn't have.
- Open Software Update using the route for your version.
- Choose the offered update or upgrade action.
- Enter the administrator password when requested.
- Allow the installation and requested restarts to finish.
The administrator password is the password used to log into that Mac. Your Apple Account can use a different password. Read the prompt before trying a different account's credentials.
Leave the lid open and let the installer work. The screen can go blank, show a progress bar and restart several times during installation. Those changes are part of the process rather than a reason to switch the power off.
After signing back in, reopen About This Mac to verify the installed version. Downloading an installer without running it doesn't change the operating system shown there.
Check App Store updates on older OS X
On OS X Mountain Lion 10.8 through macOS High Sierra 10.13, open the App Store and select Updates. Install the available system updates, following the restart prompt when one appears.
On earlier systems with the older updater, use Apple menu > Software Update. Don't look for System Settings on a Mac running Snow Leopard or Lion; those versions don't have it.
If the App Store only offers app updates, it hasn't necessarily offered the next major operating system. A separate compatible installer can be needed to move to a later release.
Updating Safari on a Mac also depends on the installed operating system. The Safari update guide explains that relationship, which matters when an old browser is the reason you're trying to update OS X.
Before choosing a large upgrade, check that your essential apps and accessories work with the version you want to install. An old printer utility or business app can be the part that needs attention, even when the Mac hardware qualifies.
Download an older compatible installer when needed
Use the official macOS download links rather than an installer mirror. The page separates App Store releases from older disk-image downloads, and links to compatibility details for supported releases.
High Sierra and several later older releases are available through linked App Store pages. Open the appropriate link in Safari on the Mac you intend to update, select Get and allow Software Update to handle the download if it opens.
For Sierra 10.12, El Capitan 10.11, Yosemite 10.10, Mountain Lion 10.8 and Lion 10.7, the download page supplies disk images. These use a different sequence from an ordinary App Store download.
- Download the compatible release's .dmg file.
- Open that disk image and double-click the .pkg file inside.
- Follow its prompts to put the macOS installer in Applications.
- Open Applications, then run Install [Version Name].
- Follow the installer until it finishes and the Mac restarts.
Opening the package puts the installer on your Mac; you still need to run that installer to upgrade the system. That extra Applications step explains why a completed package can leave About This Mac showing the original version.
Check the chosen release's requirements against your exact model and starting system. Some very old Macs need an intermediate release. The newest download on the page isn't always the one your current OS X version can upgrade to directly.
Handle an unavailable update without forcing it
A dimmed Get button or an incompatibility message can mean the selected macOS can't run on that Mac. Check the model requirement first. Repeatedly downloading the same incompatible installer won't change the hardware limit.
If Software Update says the Mac is up to date, close and reopen it to check again. Then compare the model with the release you wanted. The tool only offers compatible software, so an older computer can reach its limit at an older system.
For the specific message that an update is no longer available, the Mac update availability guide covers installing an offered update by its label. Check compatibility before choosing a command.
If installation fails, record the message, starting version, target version and model year. Ask Apple Support which upgrade path supports that machine and whether it needs an intermediate installer.
When the Mac no longer starts, ask about macOS Recovery rather than continuing a normal update procedure. A Mac with important files and no current backup needs a plan to save those files before anyone erases its disk.
The Short Version
Check About This Mac, back up and open the matching update tool. Modern Macs use Software Update; older OS X uses App Store Updates or official downloads. Run the installer from Applications, then verify the version after restarting.
Checked November 9, 2026.
Isaac Smith is the founder and editor of PC Glance, a website that covers computers, laptops, and technology. He is a tech enthusiast and a computer geek who loves to share his insights and help his readers make smart choices when buying tech gadgets or laptops. He is always curious and updated about the latest tech trends.