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Fix Microsoft 365 Voucher Already Redeemed Error
Question details
The user receives an 'already redeemed' error message when attempting to use a Microsoft 365 or Office product key on a secondary device.
- Product
- Microsoft 365 / Office 2021
- Device & OS
- not provided
- Scenario
- Attempting to install and activate Microsoft Office on an additional device, such as a tablet, after previously redeeming the voucher.
- Observed behavior
- The system rejects the product key, stating that the voucher has already been redeemed on another device.
Ensure you know the exact Microsoft account email address and password that you used when you first redeemed your Office or Microsoft 365 product key.
Sign In Using Your Linked Microsoft Account
Since product keys are only redeemed once, you must sign in with the Microsoft account linked to your active subscription to use Office on other devices.
Microsoft 365 product keys are designed to be redeemed a single time. Once redeemed, the subscription is permanently tied to your Microsoft account. You do not need to re-enter the 25-character key on secondary devices; you simply need to authenticate your account.
Launch any Microsoft Office application (such as Word or Excel) on your second device or tablet.
Tap or click on the 'Sign In' prompt when it appears upon opening the app, or navigate to the 'Account' section in the application settings.
Log in using the exact Microsoft account credentials (email and password) that are associated with your initial Microsoft 365 key activation.
Verify Your Specific Office License Type
Check whether you own a Microsoft 365 subscription or a one-time purchase like Office 2021, as multi-device licensing rules differ significantly.
Edit Documents on Any Device Free with WPS Office
Avoid restrictive device limits and confusing product key errors. WPS Office provides a lightweight, highly compatible alternative to Microsoft Office, letting you seamlessly edit files across all your devices for free.
- 1. Download WPS Office: Visit the official WPS website and click the download button to get the free installer.
- 2. Install the Software: Run the installer and follow the simple on-screen instructions to set up WPS Office on your computer or mobile device.
- 3. Open Your Files Instantly: Launch WPS Office and directly open your existing Microsoft Office files without needing any product keys.
Frequently Asked Questions
Can I use the same Microsoft 365 product key on multiple devices?
No, a product key can only be redeemed once. However, once it is redeemed and linked to your Microsoft account, you can install and sign into Microsoft 365 on multiple devices using that specific account.
Why does Office 2021 say my product key is already in use?
Unlike Microsoft 365, Office 2021 is typically a one-time purchase licensed for a single device. If you try to install it on a second computer, you will receive an error because the license is already bound to your first device.
Do I need a subscription to edit documents on a small tablet?
Not necessarily. Devices with a screen size smaller than 10.1 inches generally support basic document editing in mobile Office apps for free, without requiring an active Microsoft 365 subscription.
