Microsoft Office on Mac Will Stop Working in 2026: Here's What You Need to Know

Microsoft has announced that older versions of Office for Mac will lose the ability to connect to Microsoft 365 services starting July 13, 2026. Specifically, Office 2019 for Mac — a version released in 2018 — will no longer function properly after that date because Microsoft will not be updating a security certificate the software relies on. Windows and Android users are not affected. This applies only to Mac and iPhone users.

To understand what this means: Microsoft 365 apps use a security certificate — think of it like a passport that proves the app is trusted — to talk safely with Microsoft's servers. When that certificate expires, the app can no longer verify it is communicating securely. Microsoft normally renews this certificate through regular software updates. But since Office 2019 for Mac stopped receiving updates in October 2023, that renewal will never arrive.

What Happens After July 13, 2026

When the certificate expires, Office 2019 for Mac users will likely see error messages saying they cannot connect to Microsoft 365 services. They may be unable to open files stored in OneDrive or Outlook, unable to send emails, or find the entire application unusable for anything requiring an internet connection. There is no fix coming from Microsoft. The only solution is to switch to a newer version of Office, which requires a paid subscription rather than a one-time purchase.

Who Is at Risk

Two groups of people are affected.

The first includes anyone or any business still using Office 2019 for Mac as their main productivity software. Even though this version stopped receiving updates nearly three years ago, some organizations have held onto it — either because they update their software slowly, or because they have separate IT teams managing Macs and PCs differently. Any of these users will lose functionality in July 2026.

The second group is less obvious: iPhone users running Microsoft 365 apps on their phones. The certificate issue affects iPhones as well as Macs. If you use Microsoft Office apps on your iPhone, you should check that your apps are set to update automatically, or that your workplace IT team is keeping them current. Most iPhone users likely have automatic updates enabled and will not be affected, but it is worth confirming.

Why This Happens: Understanding End of Support

When a software company stops supporting a product, it means they no longer send out updates of any kind — not security fixes, not bug repairs, and not routine maintenance like renewing certificates. A certificate renewal does not sound like a crisis until the day the certificate expires. Unlike a security vulnerability, certificate expiry does not show up on most company IT dashboards as a warning. It simply stays invisible until the connection breaks.

We have seen this before with older Internet Explorer browsers, where organizations discovered too late that the trust certificates had expired, and suddenly users could not connect to websites. The situation is the same: a product ages past its support date, maintenance work that would normally happen automatically stops, and one day users hit a wall with no way to fix it. The difference here is that we know the date in advance.

What Needs to Happen Before July 13, 2026

If you work in IT or manage computers for a business, here are the practical steps:

Find Office 2019 for Mac. Use your company's software inventory system to see if any computers still have Office 2019 for Mac installed. Treat any found as urgent, not as something to monitor.

Check Microsoft 365 apps on iPhones. If your company manages iPhones, verify that Microsoft Office apps are current and that automatic updates are enabled. Consider forcing an update if any phones are running old versions.

Plan to move users away from Office 2019 for Mac. The supported solution is to switch to Microsoft 365, which is a monthly or annual subscription rather than a one-time purchase. This is a conversation between IT and finance teams, not just a technical task.

Mark the date. July 13, 2026 is fixed. After that, computers still running Office 2019 for Mac will have broken connectivity, not reduced performance. Stakeholders need to know this is not something that can be delayed indefinitely.

The bigger picture here is that July 2026 is a hard deadline for a problem that has been quietly building since late 2023. Organizations that have kept running Office 2019 for Mac have been operating on borrowed time. The certificate expiry is the moment when that time runs out, not the start of the problem.

If you are already using a current version of Microsoft 365 on your Mac or iPhone, simply confirm that your software updates are turned on. Your system will update automatically, and you will not be affected. The cost and the work fall only on those still using the older Office 2019 for Mac software.