Perpetual License Office Reinstall

M 0 Reputation points
2026-11-12T00:07:02.5166667+00:00

I recently replaced an older computer after a hard drive failure. When that hard drive crashed, I lost Office Professional 2021, which had a lifetime license.

I have a product key from my original purchase made through StackSocial but am unable to redeem it a second time.

Is it possible install Office on my new computer without having to re-purchase? Am I able to get a new key?

Microsoft 365 and Office | Install, redeem, activate | For home | Windows
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  1. Vikki-T 14,115 Reputation points Microsoft External Staff Moderator
    2026-11-12T10:54:12.02+00:00

    Hi M,

    I understand how frustrating it can be to lose access to a lifetime Office license after an unexpected hard-drive failure, especially when you still have the original product key and proof of purchase.

    You normally do not need to redeem the product key again or request a new one. Once an Office key has been redeemed, the license is generally associated with the Microsoft account used during the original redemption.

    Please check https://account.microsoft.com/services using the Microsoft account you originally used. If Office Professional 2021 is listed, install it from there and sign in with the same account to activate it on the replacement computer.

    If the license is not shown or activation fails, contact Microsoft Support with the original key and your StackSocial proof of purchase so they can check the license type and activation status. If Microsoft confirms that the third-party key is invalid, blocked, or not transferable, you will need to contact StackSocial regarding a replacement or refund.

    Please note that this is a user-to-user support forum. Moderators, contributors including external Microsoft employees cannot directly intervene in Microsoft product features or access back-end systems. My role is limited to providing technical guidance on reported issues, requests, or ideas.

    I know this isn't the news you were hoping for, but I wanted to make sure you got the most accurate information about your situation. Thank you so much for your understanding.     

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

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  2. AI answer

    2026-11-12T00:08:24.92+00:00

    Reinstall Office Professional 2021 from the Microsoft account used for the original redemption rather than attempting to redeem the product key again.

    Reinstall on the replacement computer

    1. Open Services & subscriptions at https://account.microsoft.com/services/.
    2. Sign in with the same Microsoft account used when the StackSocial key was first redeemed.
    3. Locate Office Professional 2021.
    4. Select Install, choose the language and 32-bit or 64-bit version if needed, and run the downloaded installer.
    5. Open Word or Excel and sign in with that same Microsoft account when prompted.

    “This product key has already been used” normally means the key was successfully redeemed and Office was added to a Microsoft account. The key is not entered again for subsequent installations or activation.[^1^](https://support.microsoft.com/microsoft-365-activation-licensing/this-product-key-has-already-been-used-error-in-office ""This product key has already been used" error in Office | Microsoft Support") Microsoft’s Office 2021 reinstall instructions use the same account-based procedure.^2^

    Try any other Microsoft accounts you owned when making the original purchase if Office 2021 is not listed. The account used to buy from StackSocial is not necessarily the Microsoft account used later to redeem the key.

    Transfer and activation

    A one-time Office 2021 license can be transferred to another computer you own. Transfers are normally limited to once every 90 days, but Microsoft permits an earlier transfer when hardware failure is the reason. The old copy must be removed and cannot remain in use; a failed drive effectively prevents its continued use.^3^

    If installation succeeds but activation reports that the maximum number of activations has been reached:

    1. Open an Office application.
    2. Follow the Activation Wizard and select the telephone activation option.
    3. Complete the telephone prompts.
    4. Explain that this is a transfer to replacement hardware after the original hard-drive failure.

    Microsoft specifically documents telephone activation for an Office 2021 transfer when the activation limit is encountered.^4^

    There is no online “deactivate” operation for perpetual Office Professional installations; reinstalling and activating on the replacement computer is the documented process.^5^

    If Office is absent from every Microsoft account

    Whether Microsoft can help depends on the actual license supplied by StackSocial:

    • Valid retail license: Contact Microsoft Support with the product key, StackSocial invoice, order confirmation, and the approximate original redemption date. A new key is not normally required because the redeemed license should be associated with the original Microsoft account. With valid proof of purchase, Support may be able to replace a key or provide another recovery option.^6^
    • “Product key is not valid” or blocked-key message: Contact StackSocial and request a valid replacement or refund. Microsoft states that a blocked key will no longer work and directs buyers of nonworking third-party keys back to the seller.[^7^](https://support.microsoft.com/microsoft-365-activation-licensing/product-key-is-not-valid-error-when-activating-office ""Product key is not valid" error when activating Office | Microsoft Support")
    • Multiple Activation Key/volume-license error: That indicates an organizational volume key rather than the normal consumer retail entitlement. Such a key is controlled by the organization that purchased it, so the reseller—not Microsoft account redemption—must resolve it.^8^

    Do not purchase another copy until the Microsoft-account installation and hardware-failure activation paths have been exhausted.

    References

    1. "This product key has already been used" error in Office | Microsoft Support
    2. Download and install or reinstall Office 2021, Office 2019, or Office 2016 | Microsoft Support
    3. Transfer your Office license to another device or another person | Microsoft Support
    4. Activate Office after reinstalling or installing on a different device
    5. [Office 2021, 2019, 2016, 2013](https://support.microsoft.com/microsoft-365-activation-licensing/office-install/deactivate-an-installation-of-office)
    6. Using product keys with Microsoft 365 | Microsoft Support
    7. "Product key is not valid" error when activating Office | Microsoft Support
    8. Can't activate Office - Microsoft Q&A
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