Office 2016 and 2019 stop connecting to Microsoft 365 in October 2026: what to do with the licenses of your Mexico operation

On September 14, 2026, the Spanish-language outlet Hipertextual reminded readers that Microsoft confirms one version of Office stops working in a month. The headline overstates it. The real story: in October 2026, Office 2016 and Office 2019 stop connecting to Microsoft 365 services.

If your Mexico office runs on machines shipped down from headquarters years ago, or bought locally with a one-time Office license, this is the month to look at them.

What stops working and what does not

What does not happen: Word and Excel do not switch off. A perpetual license is one you paid for once and own for good. The program keeps opening and the files stay on the disk.

What does happen: Microsoft stops supporting those versions for connecting to Microsoft 365, the cloud side. That means Exchange Online, which is the mail you see in Outlook, plus OneDrive, SharePoint and Teams.

In practice, the Outlook 2016 at the front desk in Querétaro may stop pulling mail on a random Monday. And there is nobody at Microsoft to call about it.

ProcessBi

Situation	Office 2016 or 2019 after October 2026
Opening and editing a file on the disk	Keeps working
Outlook with Microsoft 365 mail	May stop syncing, unsupported
OneDrive, SharePoint and Teams from Office	May fail, unsupported
Security updates	None

How to know what your Mexico office is running

On one machine, open Word, go to File, then Account. If it says Office Home and Business 2016 or 2019 and never mentions Microsoft 365, that machine is on the list.

With 20 or 30 devices, do not ask the office manager to email you screenshots. An inventory tool does it in an afternoon. In our experience there are always surprises: the accountant’s laptop with an Office installed from a disc, machines inherited from the previous general manager, or licenses bought under a US volume agreement that nobody in Mexico can find.

The real options

Option	Who it fits	What you get
Microsoft 365 Business	Offices already on Microsoft mail	Always-current Office, mail, OneDrive and Teams by subscription
Office LTSC 2024	Machines that must not change: plant floor, lab, no internet	A modern perpetual license, no cloud
Free (LibreOffice or Office in the browser)	Seats that open a file now and then	No cost, with compatibility limits

Our take: if mail already lives in Microsoft 365, Business is the short path. LTSC 2024 is for the PC running a machine on the plant floor, not for the sales team. Free tools work for the seat that opens a file once a week, as long as nobody sends it macros.

The overlap with Windows 10

ESU stands for Extended Security Updates, the paid patches that keep Windows 10 covered. Year one ends in October 2026 as well, and many machines running Office 2016 are the same ones still on Windows 10. In inherited Mexico offices that share is usually higher than headquarters assumes.

If you are going to touch the machine, decide everything at once. We wrote a guide on Windows 10 in your Mexico operation before October.

Switching Office without losing a single mailbox

What to protect before touching anything:

• PST files, where Outlook stores old mail on the disk.
• POP accounts from a previous domain that only exist on that one machine.
• Rules, signatures and autocomplete, which people miss more than you would think.

At ProcessBi we sell the licensing, run the inventory and the mail migration, and cover all of it under the IT support plan, with someone on site in Mexico when a machine needs hands.

Let’s talk

What about your Mexico operation?

If you do not know how many machines with Office 2016 or 2019 you have in Mexico, that is step one, and it takes an afternoon. Then you decide what moves to Microsoft 365, what gets LTSC and what stays on something free.

We start with a free assessment: version inventory, options with current pricing, and a plan so nobody loses their mail.

Book your free license assessment — we reply the same business day.