How to Install Office 2021 on macOS Catalina 10.15.7
Question details
The user needs to install Microsoft Office 2021 on a Mac running macOS Catalina 10.15.7, but the current installer provided by Microsoft is no longer compatible with this older operating system.
- Product
- Microsoft Office 2021
- Device & OS
- macOS Catalina 10.15.7
- Scenario
- Attempting to install the latest Office 2021 package on an older Mac (such as a 2013 iMac) that cannot be upgraded past macOS Catalina.
- Observed behavior
- The current Office 2021 installer fails to run and displays a compatibility error because it requires a newer version of macOS, blocking the installation completely.
Ensure you have your valid Microsoft Office 2021 product key or account credentials ready, and temporarily close any running applications before beginning the legacy installation process.
Download and Install an Older Compatible Build (Version 16.66)
Use the official Office for Mac update history to download a legacy installer (such as version 16.66) that still officially supports macOS Catalina.
Microsoft continuously updates the Office installer, which often removes support for older macOS versions. To bypass this, you must download an older build released before support for Catalina was discontinued.
Open your web browser and navigate to the official Microsoft 'Update history for Office for Mac' page.
Scroll through the release list to find the October 2022 release (Version 16.66), which is generally the last major version to officially support macOS Catalina.
Click the download link for the full Office suite installer package next to version 16.66.
Once downloaded, open the .pkg file and follow the on-screen prompts to install Office 2021 on your Mac.
Open Word or Excel, go to 'Help' > 'Check for Updates' in the top menu bar, and uncheck 'Automatically keep Microsoft Apps up to date' so it does not attempt to install an incompatible newer version.
Request a Legacy Installer Link via Microsoft Support
If you are unable to locate the correct historical build on the website, Microsoft Support can provide you with a direct download link for Catalina.
Try WPS Office for Older Macs
If finding and configuring legacy installers for Microsoft Office 2021 on macOS Catalina feels tedious, WPS Office offers a powerful, lightweight alternative. It avoids frustrating OS compatibility limits while providing seamless document editing for your Mac.
- 1. Download the Installer: Visit the official WPS Office website and click the download button for macOS.
- 2. Install on Mac: Open the downloaded .dmg file and drag the WPS Office icon into your Applications folder.
- 3. Start Creating: Launch WPS Office from Launchpad, sign in, and immediately begin opening your existing Microsoft Office files.
Frequently Asked Questions
Can I install the latest Microsoft Office updates on macOS Catalina?
No, the latest Microsoft Office updates require macOS Monterey or a newer operating system. For Catalina, you must remain on older supported builds, such as version 16.66.
Why does the standard Office 2021 installer reject macOS Catalina?
Microsoft policy only supports the three most recent major versions of macOS. Once Catalina fell out of this window, standard installers were updated to block it, requiring users to manually seek out legacy installer builds.
How do I stop Microsoft AutoUpdate from upgrading to an incompatible version?
Open any Office application like Word, click 'Help' in the top menu, select 'Check for Updates', and turn off the toggle or uncheck the box for keeping Microsoft Apps automatically up to date.
