Office Home & Business 2021 activation. Product key redeemed in 2022. License no longer activates.

Question

Office Home & Business 2021 activation. Product key redeemed in 2022. License no longer activates.

C.S 0

I purchased Office Home & Business 2021 in October 2022. It has worked on this Mac for nearly three years. After restarting my computer, Word now says 'License Not Activated.' I still have the original purchase receipt and product key, but I don't know which Microsoft account the key was originally redeemed with. Can you locate the license and help me reactivate it?

Deepshikha Seth 0 Reputation points

2026-07-24T11:20:36.69+00:00

Hi! i am facing the same issue. I have upgraded my Mac OS to Tahoe 26.5.2 but still facing the same issue. I have Office Home and Business 2019 for Mac, yet getting an error mesage: No Licence Found.

Using Office 16.106.
Tried with a earler version 16.45 on your team memebrs suggestion, but that also didn't work.
Please help.
EmilyS_726 29,390 Reputation points Volunteer Moderator

2026-07-24T14:36:15.0866667+00:00
@Deepshikha Seth Your issue is NOT the same. For your scenario, the issue is the 2019 version itself, it has nothing to do with what macOS you are using.

Starting July 13, 2026, Office 2019 for Mac entered reduced functionality mode because its licensing certificate can no longer be updated. Office may still open documents, but it can no longer activate for editing, saving, or creating files. The 0x0 error is part of that activation failure.

Microsoft confirms that Office 2019 for Mac cannot be updated to the required version, and reinstalling Office 2019 will not resolve it.

The available options are:

Use Word, Excel, and PowerPoint online for free through Microsoft 365 for the web.

Purchase a supported version such as Office Home 2024.

Subscribe to Microsoft 365.

Your existing documents are not deleted or damaged, but Office 2019 for Mac can no longer be restored to full editing mode through activation troubleshooting.

https://support.microsoft.com/office/update-microsoft-365-or-office-on-your-macos-or-ios-device-f418ae5d-bb5f-4078-b3d9-9340f5dd084e?apid=ets

If you have any further question, please start your own thread so that OP for this thread won't be bombarded by email notification of our communication.

Answer recommended by moderator

EmilyS_726 29,390 Volunteer Moderator

I don't t think I explained well to you.

The issue is not about your 2021 license.

The issue is about your MacOS. You are running a MacOS version lower than 12, that's the problem. If you read the article I sent you in my last reply, on July 13th, Microsoft requires Mac devices to have updated digital certificates in order to keep Office products activated. However, this updated certificate can only work on MacOS 12 and above. Since yours is below 12, your device will not receive this important update, hence your Office product cannot be activated and will enter what it is now called "reduced functionality mode".

So your options are:

Use web version via web browser.
Use your license on a supported Mac device running MacOS 12 or above.
3.Update your MacOS to 12 or above if the device supports it.

0 comments

2 additional answers

Your answer

Deepshikha Seth 0 Reputation points

2026-07-24T11:20:36.69+00:00

Hi! i am facing the same issue. I have upgraded my Mac OS to Tahoe 26.5.2 but still facing the same issue. I have Office Home and Business 2019 for Mac, yet getting an error mesage: No Licence Found.

Using Office 16.106.
Tried with a earler version 16.45 on your team memebrs suggestion, but that also didn't work.
Please help.
EmilyS_726 29,390 Reputation points Volunteer Moderator

2026-07-24T14:36:15.0866667+00:00

@Deepshikha Seth Your issue is NOT the same. For your scenario, the issue is the 2019 version itself, it has nothing to do with what macOS you are using.

Starting July 13, 2026, Office 2019 for Mac entered reduced functionality mode because its licensing certificate can no longer be updated. Office may still open documents, but it can no longer activate for editing, saving, or creating files. The 0x0 error is part of that activation failure.

Microsoft confirms that Office 2019 for Mac cannot be updated to the required version, and reinstalling Office 2019 will not resolve it.

The available options are:

Use Word, Excel, and PowerPoint online for free through Microsoft 365 for the web.

Purchase a supported version such as Office Home 2024.

Subscribe to Microsoft 365.

Your existing documents are not deleted or damaged, but Office 2019 for Mac can no longer be restored to full editing mode through activation troubleshooting.

https://support.microsoft.com/office/update-microsoft-365-or-office-on-your-macos-or-ios-device-f418ae5d-bb5f-4078-b3d9-9340f5dd084e?apid=ets

If you have any further question, please start your own thread so that OP for this thread won't be bombarded by email notification of our communication.

Answer 1

GsN5034 - IA 77,095 Independent Advisor

Hello, thank you for reaching out to Microsoft Q&A.

You can sign in with each of your Microsoft accounts on the Services & Subscriptions page one by one to see which account your Office Home & Business 2021 license is linked to.

https://account.microsoft.com/services

Open an InPrivate/Incognito browser window and sign in with your accounts one at a time. Use a separate tab for each account and check which one shows the Office Home & Business 2021 license.

Once you’ve identified the correct account, you can use the Office license removal tool to remove all previous traces of the Office license from your device and then reactivate it.

How to remove Office license files on a Mac

Let me know if you still need more help.

GsN5034 - IA 77,095 Reputation points Independent Advisor

2026-07-17T16:14:36.4433333+00:00

Hello,

As mentioned in the article shared by Emily S above, for the Office apps to work, your Mac must be running macOS 12 (Monterey) or later.

So, the only option here is to upgrade your macOS in order to continue using Office 2021 on your device.

Reference-

Update Microsoft 365 or Office on your macOS or iOS device

Answer 2

EmilyS_726 29,390 Volunteer Moderator

What MacOS version are you using?

C.S 0 Reputation points

2026-07-17T14:06:05.0766667+00:00

11.7.11 and I am not able to update to a different version.
EmilyS_726 29,390 Reputation points Volunteer Moderator

2026-07-17T14:30:39.52+00:00

Ok, then the issue here is your MacOS.

If your OS is above version 12 but below 14, your office products can be functional, but Microsoft no longer maintains or updates that version. In this scenario, you can install the older downgraded version.

However, if it is below 12, it will now enter reduced functionality mode. In another word, the OS is too old to receive the licensing update the Office now requires, so it will now operate in reduced functionality mode. Sorry.

https://support.microsoft.com/office/update-microsoft-365-or-office-on-your-macos-or-ios-device-f418ae5d-bb5f-4078-b3d9-9340f5dd084e
C.S 0 Reputation points

2026-07-17T15:54:32.59+00:00

I have a perpetual Office Home & Business 2021 for Mac license associated with my Microsoft account. I'm running Office 16.77 on macOS Big Sur 11.7.11. I performed a clean reinstall, verified the Office Licensing Helper is installed, and confirmed my login keychain is healthy. Word begins activation but always fails with "Unknown Error (0x0)" and reports "Unable to Activate Microsoft 365." My Office 2021 license still appears under my Microsoft account.
C.S 0 Reputation points

2026-07-17T16:20:57.7233333+00:00

Thank you for the clarification. I appreciate your help.

I do have one question, though. My understanding is that Microsoft still provides Office 16.77 specifically for macOS Big Sur (11.x), and my Office Home & Business 2021 perpetual license is correctly associated with my Microsoft account.

My Mac is a Mid-2014 MacBook Pro, and macOS 11.7.11 (Big Sur) is the newest officially supported operating system for my hardware. Upgrading to macOS 12 or later is not an option without using unsupported third-party methods.

Is there an official Microsoft article stating that, as of July 13, Microsoft now requires macOS 12 or later for Office activation due to updated digital certificates? If so, could you provide a link?

If that is indeed the case, it would appear that customers with perpetual Office 2021 licenses and Macs that cannot officially run macOS 12 or later have no supported way to activate software they previously purchased. I'd like to understand whether this is an intentional policy change or whether there is another supported activation method for users in this situation.

Thank you.
EmilyS_726 29,390 Reputation points Volunteer Moderator

2026-07-17T16:46:30.2633333+00:00

Is there an official Microsoft article stating that, as of July 13, Microsoft now requires macOS 12 or later for Office activation due to updated digital certificates? If so, could you provide a link?

Yes, that's the link I shared with you in a previous comment, but I will share again. https://support.microsoft.com/office/update-microsoft-365-or-office-on-your-macos-or-ios-device-f418ae5d-bb5f-4078-b3d9-9340f5dd084e

My understanding is that Microsoft still provides Office 16.77 specifically for macOS Big Sur (11.x), and my Office Home & Business 2021 perpetual license is correctly associated with my Microsoft account.

However, the issue is about the digital certificate that required update in order for even an older version like 16.77 to stay activated. But this certificate update cannot happen on MacOS 12 or lower, hence, installing 16.77 will not help as it will still run into activation issue. Does that make sense?

If that is indeed the case, it would appear that customers with perpetual Office 2021 licenses and Macs that cannot officially run macOS 12 or later have no supported way to activate software they previously purchased. I'd like to understand whether this is an intentional policy change or whether there is another supported activation method for users in this situation.

Your understanding is correct. It is a policy change but based on technical limitations when it comes to older Mac devices that cannot handle the digital certificate update. There is NO other activation method.