How to fix M365 excel as it is saying to update the product key

For Microsoft 365 Personal or Family, activate Excel by signing in with the Microsoft account linked to the subscription rather than entering or updating a product key.^1^

1. Verify the subscription and account

1. Close Excel and all other Office applications.
2. Open the Microsoft account Services & subscriptions page: https://account.microsoft.com/services/
3. Sign in with the personal Microsoft account used to purchase Microsoft 365.
4. Confirm that Microsoft 365 Personal or Microsoft 365 Family appears and is Active.
   • If it is expired, renew it.
   • If it is missing, try the other personal email address that may have been used for the purchase.
5. Reopen Excel and select Sign in on the activation window. Use the same account shown on the Services & subscriptions page. Do not select the product-key option unless you have a new, unused retail key.^1^

2. If someone else owns the Family subscription

If the Microsoft 365 Family plan belongs to another person:

1. Ask the subscription owner to share Microsoft 365 Family with your Microsoft account.
2. Open the invitation and accept it while signed in to that account.
3. Sign in to Excel using the same invited account.
4. If the current installation still does not activate, go to https://account.microsoft.com/services/ using the invited account and install Microsoft 365 from there.

A product key from the subscription owner should not be reused for a family member’s installation; activation is tied to the account that accepted the sharing invitation.^2^

3. Run the activation troubleshooter

If the subscription is active and Excel still requests a key:

1. On the affected PC, open Microsoft’s activation troubleshooting page below.
2. Start the Microsoft 365 activation troubleshooter.
3. When prompted that the site is trying to open Get Help, select Open.
4. Complete the prompts and restart Excel.

The troubleshooter must run on the PC containing Microsoft 365 and requires Windows 10 or later.^3^

4. Remove conflicting Office installations

Multiple Office installations can cause activation conflicts:

1. Select Start, search for Control Panel, and open it.
2. Select Programs > Programs and Features.
3. Search the installed-program list for Office.
4. If multiple versions are listed, uninstall only the old or unused versions.
5. Restart Windows, open Excel, and sign in again.

If only one version is installed—or removing the duplicate does not help—run an Online Repair:

1. Right-click Start and select Installed apps.
2. Find Microsoft 365, select the three-dot menu, and choose Modify.
3. Select Online Repair > Repair.
4. Restart Windows and sign in to Excel again.^3^

Special case: newly purchased retail key

Only use a product key if you bought a new, unused Microsoft 365 card or key from a retailer. Redeem it once at https://www.microsoft365.com/setup; afterward, activation uses the Microsoft account associated with that key.^4^

If activation still fails after Online Repair, completely uninstall Microsoft 365 and reinstall it from the active account’s Services & subscriptions page. This removes damaged activation components, but ensure documents are saved before uninstalling.

References

1. Using product keys with Microsoft 365 | Microsoft Support
2. Where do I find product key for Microsoft 365 Family subscription? Family member prompted for product key when opening Excel. - Microsoft Q&A
3. Unlicensed Product and activation errors in Office | Microsoft Support
4. Activate Office for Windows | Microsoft Support