Office Asks for a Product Key Again After Activation
If Office was already activated but suddenly requests a product key again, it’s usually a sign that Office can’t confirm the activation state at the moment. This can happen after updates, account changes, or when the installed Office edition doesn’t match what was originally set up.
Why this can happen
Office may ask again if:
Windows was updated or reinstalled recently
Office was signed in with a different Microsoft account than before
The installed Office edition doesn’t match the one you intended to use
Activation files were damaged or removed
How to fix it
Restart your PC
Before doing anything else, restart your computer. In many cases, this refreshes the activation status and the message disappears.Confirm you’re using the correct Office edition
Go to Control Panel > Programs > Programs and Features and verify the Office version installed.
Make sure it matches what you’re trying to use (for example, an Office 2021 edition instead of “Microsoft 365 Apps”).
Sign out of Office accounts and sign back in only if needed
Open any Office app and go to File > Account.
Sign out of all accounts shown there, close the app completely, then reopen it and check if the prompt is gone.Enter your product key again
In the same Office app, go to File > Account > Change Product Key and enter the key you received.Repair the Office installation
Go to Control Panel > Programs, select Microsoft Office, then choose Change.
Run Quick Repair first. If the issue continues, try Online Repair and then restart the PC.