Can I buy a version of Microsoft 365 which will work with Mac OS Big Sur?

Question

Can I buy a version of Microsoft 365 which will work with Mac OS Big Sur?

linda davies 10

My computer is too old to support macOS Monterey and I understand that starting on 13 July a security certificate will be required which will then switch my documents to view only. I only want to use Word and Excel and still want to use my currently documents

Anita Chadwick 10 Reputation points

2026-07-14T00:18:01.0133333+00:00

Same problem here! I have an older computer that works great. I have had no issues until today. I can no longer use my Microsoft office and I had an original hard disk install from 2021 and then it updated today and I can no longer use it and do not have my office product key on the last update I did. I have an older Mac that has a new hard drive and works great. I do not want to update my computer for this and am so frustrated. I am on Big Sur 11.7.11
Max Henry 0 Reputation points

2026-07-14T01:56:26.0566667+00:00

@Anita Chadwick I'm in the same boat. Have a MacBook that still works fine but is too old to update the OS. Now I'm paying for a subscription that I can only use on half my devices. Also don't recall getting notification of this change - today's Google search is the first I've heard of it. Microsoft's customer service the last few years has been terrible.
Ruth Horsfall 0 Reputation points

2026-08-13T02:03:30.33+00:00

Same problem here. It's also not working on my laptop that I was able to upgrade to Monterey, with a widely reported 0x0 error popping up. I might buy a standalone suite as advised, but I'm concerned this will end up with the same problem. It's unconscionable behaviour by Microsoft.
Anita Chadwick 0 Reputation points

2026-08-20T01:27:44+00:00

It is infuriating as I have an even OLDER mac desktop from 2011 and my software works fine because I have the disk!

I did go and purchase office 365 online and STILL CANNOT USE IT EVEN THOUGH I PAID YET AGAIN!!!! I paid for nothing as it will not work with the online format.

This should be illegal in all honesty. I have paid for the software and should be able to use it. I do not want to go buy a new computer when mine works perfectly fine!

2 answers

Your answer

Anita Chadwick 10 Reputation points

2026-07-14T00:18:01.0133333+00:00

Same problem here! I have an older computer that works great. I have had no issues until today. I can no longer use my Microsoft office and I had an original hard disk install from 2021 and then it updated today and I can no longer use it and do not have my office product key on the last update I did. I have an older Mac that has a new hard drive and works great. I do not want to update my computer for this and am so frustrated. I am on Big Sur 11.7.11
Max Henry 0 Reputation points

2026-07-14T01:56:26.0566667+00:00

@Anita Chadwick I'm in the same boat. Have a MacBook that still works fine but is too old to update the OS. Now I'm paying for a subscription that I can only use on half my devices. Also don't recall getting notification of this change - today's Google search is the first I've heard of it. Microsoft's customer service the last few years has been terrible.
Ruth Horsfall 0 Reputation points

2026-08-13T02:03:30.33+00:00

Same problem here. It's also not working on my laptop that I was able to upgrade to Monterey, with a widely reported 0x0 error popping up. I might buy a standalone suite as advised, but I'm concerned this will end up with the same problem. It's unconscionable behaviour by Microsoft.
Anita Chadwick 0 Reputation points

2026-08-20T01:27:44+00:00

It is infuriating as I have an even OLDER mac desktop from 2011 and my software works fine because I have the disk!

I did go and purchase office 365 online and STILL CANNOT USE IT EVEN THOUGH I PAID YET AGAIN!!!! I paid for nothing as it will not work with the online format.

This should be illegal in all honesty. I have paid for the software and should be able to use it. I do not want to go buy a new computer when mine works perfectly fine!

Answer 1

There is no separate “older” Microsoft 365 subscription that avoids the July 13, 2026 certificate change. The change applies to all Microsoft 365 subscription apps on macOS and iOS, regardless of when the subscription was purchased.

Key points from the current guidance:

Certificate change on July 13, 2026

Microsoft 365 apps on macOS use a licensing certificate that expires on July 13, 2026.
After that date, any Microsoft 365 apps (Word, Excel, PowerPoint, Outlook, OneNote) that are below the required minimum version will go into reduced functionality mode.
In reduced functionality mode, it is still possible to open, view, and print existing files, but not edit, save, Save As, or create new files.
No documents are deleted or lost; functionality is restricted until the apps are updated.

Minimum supported versions after July 13, 2026

For macOS, Microsoft 365 apps must be at version 16.83 or later and the OS must be macOS 12 (Monterey) or later for the apps to keep working normally after July 13, 2026.
Devices that cannot be upgraded to at least macOS 12 will not meet the minimum requirement and their Microsoft 365 apps will end up in reduced functionality mode after the certificate expires.

Impact on a Mac stuck on Big Sur

Big Sur is older than macOS 12 Monterey, so it does not meet the minimum OS requirement listed for Microsoft 365 apps after July 13, 2026.
Because of that, there is no Microsoft 365 subscription variant that will keep full editing capability on Big Sur after the certificate expiry.
Any Microsoft 365 subscription apps running on Big Sur will eventually:
- Continue to open and view documents.
- Lose the ability to edit, save, or create new documents after July 13, 2026, once the certificate is considered expired for that app version.

Options to keep editing Word and Excel documents Given the constraints in the current guidance, the supported options are:

Upgrade hardware/OS: Move to a Mac that can run at least macOS 12 (Monterey) so Microsoft 365 apps can be updated to version 16.83 or later and keep full functionality.
Use Microsoft 365 for the web: Even on an older Mac, a supported browser can be used to access Word and Excel on the web at microsoft.com. Web access is included with Microsoft 365 subscriptions and allows editing documents without relying on the local Mac app version.
Transition to supported hardware over time: The admin guidance explicitly recommends migrating users to hardware that meets the minimum OS requirements when devices cannot be upgraded.

There is no way, within the current Microsoft 365 subscription model, to buy a special “Big Sur–only” Microsoft 365 that will continue to allow local editing in the desktop apps beyond the July 13, 2026 certificate deadline. To keep editing locally in Microsoft 365 apps, the device must meet the minimum OS and app version requirements; otherwise, use Microsoft 365 for the web or move to newer hardware.

References:

Answer 2

Ivan B 120.7K Independent Advisor

Hii,

In this case, although it's possible to install this version and use Office 365, be aware that there is information suggesting that older versions of Office for Mac may not work on Big Sur.

Big Sur (Office 365 and 2019/2021): https://officecdn.microsoft.com/pr/C1297A47-86C4-4C1F-97FA-950631F94777/MacAutoupdate/Microsoft_365_and_Office_16.77.23091003_Installer.pkg

After July 13th, Office 365 will no longer work on your Mac, so I recommend not subscribing. https://support.microsoft.com/en-us/office/update-microsoft-365-or-office-on-your-macos-or-ios-device-f418ae5d-bb5f-4078-b3d9-9340f5dd084e

In short, if you have an Office 365 subscription, the Big Sur version of Office will no longer work after July 13.

In that case, you would only be able to use the commercial version of Office for Mac; you will need an Office 2019 or 2021 license.

Thanks

Ivan B 120.7K Reputation points Independent Advisor

2026-06-02T06:06:51.77+00:00

Hi,

I hope everything is going well?

I just wanted to know if you're still having the problem?

I'd like to share it so we can check the situation.

Thanks
Ruth Horsfall 0 Reputation points

2026-08-14T01:03:43.13+00:00

@Ivan B I'm looking at purchasing Office 19, but it sounds like this may have been affected by the July 13 changes, too. My Office 16 has certainly stopped working since then (as well as Office 365). I've worked around the issue on my laptop, which I (finally) was able to upgrade to Monterey and install Office 365 16.88, but my main computer is stuck on Big Sur. Makes me angrier than the One Drive debacle from a year or two ago, but at least my PhD is finished now. It would have been an unmitigated disaster last year for me.