For MacOS versions 10.10 to 10.12.6, a separate installer of Microsoft Office is required as the current versions will not work on these systems. These versions are supported by the Microsoft Office 365 license.
Download the Microsoft Office 365 installer for MacOS versions 10.10 to 10.12.6:
From the official Microsoft website
You can purchase a license for this installer (Microsoft Office 365 Pro Plus) from our catalog on the following page. The Office 365 package includes 5 TB of OneDrive cloud storage.
