lost microsoft office

Reinstall Office by signing in with the same Microsoft account—or work/school account—that was associated with Office before the computer was reinstalled.

Reinstall Office

1. Open Microsoft account Services & subscriptions.
2. Sign in with the account originally used to purchase, redeem, or activate Office.
3. Find Microsoft 365 or your one-time-purchase Office product.
4. Select Install, run the downloaded installer, and follow its prompts.
5. Open Word or Excel and sign in with that same account to activate it.

If a product key reports “This product key has already been used,” do not redeem it again. That means the key was previously added to a Microsoft account; install and activate with that account instead.[^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")

For Microsoft 365 or Office 2024, another supported route is to sign in at m365.cloud.microsoft/apps, select Install apps, and then run the installer.^2^

If Office is not listed

• Try every personal Microsoft account that might have been used when Office was purchased or first activated.
• If it was supplied by an employer or school, sign in with that organization’s account. Contact its administrator if the license or account is missing.
• If the username or password has been forgotten, use Microsoft’s account-identification and recovery options. Microsoft Support cannot access or change account details on your behalf.^3^

If Office 2021 came preinstalled

Some preinstalled Office 2021 products were activated without a product key or Microsoft account. For that specific case:

1. Open Start → Microsoft Store.
2. Select Library → Apps or All.
3. Turn off Show installed products only, if displayed.
4. Find Office and select the Cloud download button.
5. Complete the installation prompts.^4^

If Office came bundled with the computer but appears neither in the Microsoft account nor the Store library, contact the computer manufacturer for its recovery procedure. Do not purchase another license until these account and Store options have been checked.

References

1. "This product key has already been used" error in Office | Microsoft Support
2. Download, install, or reinstall Microsoft 365 or Office 2024 on a PC or Mac
3. I forgot the account I use with Microsoft 365
4. Reinstall Office from the Microsoft Store app | Microsoft Support