This usually means Word is no longer seeing a valid license for the installed Office app, so it switches into reduced functionality mode. In that state, documents can still be opened and printed, but editing and saving are blocked.
Common reasons this appears suddenly:
- The installed app is a Microsoft 365 build, but there is no active subscription tied to the signed-in account.
- Word is signed in with the wrong Microsoft account, so it cannot find the license that was originally used.
- A trial or previous subscription expired.
- Office could not verify the subscription/license for a long time because it needs to connect to the internet periodically.
- The product is showing as Unlicensed Product or has an activation error.
What happens if nothing is done:
- Office eventually runs in reduced functionality mode.
- Documents can be opened and printed.
- Documents cannot be edited or newly created.
What to check first:
- In Word, go to File > Account.
- Check which account is signed in.
- If the wrong account is shown, sign out and sign in with the Microsoft account that was used to buy or redeem Office.
- Look at Product Information. If it shows Microsoft 365 but the purchase was a one-time license, the installed copy may not match the owned license.
- Check the license on the Microsoft account Services & subscriptions page. If there is an active Microsoft 365 subscription, it should appear there. If there is no subscription, that explains the subscription prompt.
If the installed copy and license do not match, uninstall and reinstall Office from the account that owns the license. Microsoft also provides an uninstall troubleshooter for Windows PCs.
If internet verification is the issue, reconnect to the internet and choose Retry. Office needs to verify subscription status intermittently, and after an extended period offline it can show Couldn't Verify Subscription and move toward reduced functionality mode.
If urgent access is needed, Microsoft 365 for the web apps can be used in a browser at microsoft365.com.