download an older version of 365

An older iMac that cannot install the newest Microsoft 365 for Mac can still use an older supported Office/365 build, as long as there is a valid Microsoft 365 or Office license that can activate it.

Key points and actions:

1. Verify that the Mac’s OS version is supported by an older Office build.
   • For older macOS versions (such as Monterey 12.x), current Microsoft 365 installers may show an “OS too old” or “unsupported” message.
   • In that case, install the most recent Office version that still supports that macOS release instead of the latest Microsoft 365 for Mac build.
2. Use an existing Microsoft 365 or Office license to activate the older build.
   • A current Microsoft 365 subscription (for example, Microsoft 365 Personal or Family) can activate an older Office for Mac version that still runs on the iMac.
   • If there is a previously purchased perpetual license (for example, Office 2021 or Office 2019 for Mac) that supports the iMac’s OS, that license can also be used to activate the installed apps.
3. Download and install the appropriate older Office for Mac version.
   • Sign in with the Microsoft account that owns the Microsoft 365 subscription or Office license.
   • Install the most recent Office version that is compatible with the Mac’s OS (for example, an Office 365 for Mac 16.88.x build for macOS Monterey, as referenced in the Q&A content).
   • After installing, run Help > Check for Updates once to move to the final supported build for that version (for example, 16.88.1 for Outlook and PowerPoint in the Monterey scenario). Automatic updates are not required if no newer compatible builds exist.
4. If the newest Microsoft 365 installer fails on the Mac:
   • This is expected if the OS is not supported by the current Microsoft 365 for Mac system requirements.
   • In that case, do not attempt to force-install the latest build; instead, use the last Office build that supports the Mac’s OS and activate it with the existing subscription or license.

If the iMac is running an OS version that is below the minimum supported for any current or archived Office for Mac build, Microsoft 365 apps cannot be installed locally and Microsoft 365 apps for the web in a browser must be used instead.

References:

• Download, install, or reinstall Microsoft 365 or Office 2024 on a PC or Mac
• How to revert to an earlier version of Office
• Plan an upgrade from older versions of Office to Microsoft 365 Apps
• where can i find an old version of Office 365 for mac - Microsoft Q&A
• Office running on OS 12.7.6 - Microsoft Q&A
• Cannot install Microsoft 365 because my os is too old - Microsoft Q&A