Product Key Issues

How to Fix 'This Product Key Has Already Been Redeemed' in Office 2021

Algirdas Jasaitis Oct 7, 2026 870 views

Question details

The user is unable to activate Office 2021 because their product key is recognized as already used.

How to Fix 'This Product Key Has Already Been Redeemed' in Office 2021

Product: Microsoft Office 2021
Device & OS: not provided
Scenario: Activating or transferring an Office 2021 installation to a new or existing computer.
Observed behavior: The system rejects the product key and displays a 'This product key has already been redeemed' error message.

Before you start

Ensure you have access to all Microsoft accounts you might have used previously, as the product key is permanently linked to the account used during the first activation.

Solution 1Recommended

Install Office 2021 Directly from Your Microsoft Account

Since the product key can only be redeemed once, you must download and install Office from the Microsoft account it is already linked to.

Once a Microsoft Office product key is redeemed, it is no longer needed for installation. The license becomes permanently attached to your Microsoft account profile.

Sign in to Microsoft Services

Open a web browser and navigate to https://account.microsoft.com/services. Sign in with the Microsoft account you originally used to redeem the key.

Locate your Office License

Scroll to the 'Services & subscriptions' section and look for your Microsoft Office 2021 purchase.

Download the Installer

Click the 'Install' button next to the Office 2021 product name to download the setup file to your computer.

Run the Setup

Open the downloaded installation file and follow the on-screen prompts to complete the setup without needing the product key.

Install Office 2021 Directly from Your Microsoft Account

Account Found: If you see your Office 2021 license listed, you have successfully located the correct Microsoft account.

Solution 2

Transfer Your Office 2021 License to a New Computer

If you are trying to move Office 2021 to a different computer, you must first uninstall it from the original device.

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Avoid Product Key Hassles with WPS Office

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1. Download the Installer: Visit the official WPS Office website and click the free download button.
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3. Start Creating: Open WPS Office and immediately start working on your documents, spreadsheets, and presentations without needing a product key.

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Frequently Asked Questions

Can I use my Office 2021 product key more than once?

No. A Microsoft Office 2021 product key can only be redeemed once. Upon its first use, the license is permanently bound to the Microsoft account used during the redemption process.

How do I find which Microsoft account is linked to my product key?

You can check by signing into any Microsoft accounts you own at account.microsoft.com/services. Look under the 'Services & subscriptions' tab; if your Office 2021 license appears there, you have found the correct account.

What should I do if I forgot the Microsoft account email?

Try signing in with any alternative email addresses or phone numbers you frequently use. If you still cannot find it, use the Microsoft account recovery page and follow the prompts to recover your associated email address.

Installation & Activation