I purchased Microsoft Office Home & Business 2021 for Mac on December 28, 2021, with a perpetual license—not a Microsoft 365 subscription.
On October 24, 2026, I discovered that Excel would no longer allow me to save spreadsheets. Instead, Microsoft presented subscription activation options.
My Microsoft account still showed my legitimate Office 2021 purchase.
The installed Excel version was 16.114.1, which reported that my Office 2021 license was unsupported.
Microsoft's own installation page downloaded that same incompatible version, even though I was signed into the account associated with my Office 2021 purchase.
I eventually resolved the problem by locating Microsoft's October 6, 2026 installer, Version 16.113.4, removing the newer Office applications, and reinstalling the older version.
Excel immediately recognized my Office Home & Business 2021 license, and saving worked again.
My concern: Microsoft appears to have automatically updated my legitimately purchased software to a version that would no longer accept my perpetual license.
Ending support for an older product is understandable. Disabling essential functionality through an automatic update is not.
Microsoft should explain why this happened, prevent incompatible updates for perpetual-license customers, and provide a straightforward recovery process that does not steer customers toward purchasing subscriptions.
Other Office 2021 Mac users experiencing this problem should know that reinstalling a compatible version may restore their existing license without purchasing Microsoft 365.