Update Office from the Mac App Store. If you downloaded Office from the Mac App Store, and have automatic updates turned on, your apps will update automatically. But you can also manually download the updates: Open the Mac App Store from your Dock or Finder. Click the Apple menu and select 'App Store.' The Apple menu is in the upper-left corner of the screen. You can now use the App Store to check for the latest versions of your App Store apps, as well as install any security and stability updates for OS X. You download a 5 GB Mac OS X installer from the App Store, the machine restarts, your system is upgraded to Mac OS X Yosemite or El Capitan but wait, where has the installer disappeared? Your Mac, in a bid to save space, deletes the original installer automatically after the upgrade and thus you cannot reuse it on other machines.
If you attempt to download and install an App Store update, you may receive an error message about the update not being found. If you re-attempt to download the update, you receive the same message repeatedly.
In most cases, you likely are trying to download an update that is outdated or has been combined with a newer update (if you last opened the App Store with an update you never installed). To fix this, quit the app store and re-open it again. The App Store will reach out to Apple’s update servers and find the most up-to-date updates for your Mac OS and apps. You should be able to download and install updates normally again.
Mac App Store Update
However, if the error message is occurring for a specific update, try to manually update the app from the developer by downloading the most update to version or download the Mac OS update manually by searching for it on their support website here.
Mac App Store Download
All else, Apple’s update servers may be experiencing technical issues preventing updates from downloading to your computer. Try to wait a bit and check Apple’s system statuses on their website here.
To get the latest features and maintain the security, stability, compatibility, and performance of your Mac, it's important to keep your software up to date. Apple recommends that you always use the latest macOS that is compatible with your Mac.
Learn how to upgrade to macOS Big Sur, the latest version of macOS.
Check compatibility
If a macOS installer can't be used on your Mac, the installer will let you know. For example, it might say that your Mac doesn't have enough free storage space for the installation, or that the installer is too old to be opened on this version of macOS.
If you want to check compatibility before downloading the installer, learn about the minimum requirements for macOS Catalina, Mojave, High Sierra, Sierra, El Capitan, or Yosemite. You can also check compatible operating systems on the product-ID page for MacBook Pro, MacBook Air, MacBook, iMac, Mac mini, or Mac Pro.
Make a backup
Before installing, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.
Download macOS
It takes time to download and install macOS, so make sure that you're plugged into AC power and have a reliable internet connection.
These installers from the App Store open automatically after you download them:
- macOS Catalina 10.15 can upgrade Mojave, High Sierra, Sierra, El Capitan, Yosemite, Mavericks
- macOS Mojave 10.14 can upgrade High Sierra, Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion
- macOS High Sierra 10.13 can upgrade Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion, Lion
Your web browser downloads the following older installers as a disk image named InstallOS.dmg or InstallMacOSX.dmg. Open the disk image, then open the .pkg installer inside the disk image. It installs an app named Install [Version Name]. Open that app from your Applications folder to begin installing the operating system.
- macOS Sierra 10.12 can upgrade El Capitan, Yosemite, Mavericks, Mountain Lion, or Lion
- OS X El Capitan 10.11 can upgrade Yosemite, Mavericks, Mountain Lion, Lion, or Snow Leopard
- OS X Yosemite 10.10can upgrade Mavericks, Mountain Lion, Lion, or Snow Leopard
Install macOS
Follow the onscreen instructions in the installer. It might be easiest to begin installation in the evening so that it can complete overnight, if needed.
If the installer asks for permission to install a helper tool, enter the administrator name and password that you use to log in to your Mac, then click Add Helper.
Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar, or show a blank screen several times as it installs both macOS and related updates to your Mac firmware.
Learn more
You might also be able to use use macOS Recovery to reinstall the macOS you're using now, upgrade to the latest compatible macOS, or install the macOS that came with your Mac.