How to Reactivate Office 365: Step-by-Step Guide

Updated 14 November 2026 · Standard formula, shown below

This guide walks you through reactivating your Microsoft 365 (formerly Office 365) subscription after it has expired, been disabled, or is showing an activation error. You’ll learn how to check your subscription status, renew or re-enter your product key, and get your Office apps working again on both Windows and Mac.

What You’ll Need

Your Microsoft account email and password (the one used to purchase or sign up for Office 365)
The product key (if you bought a retail card or from a third-party retailer)
An active internet connection
Administrator access to your computer (to install or repair Office)

Step-by-Step

Check your subscription status. Go to account.microsoft.com/services and sign in with the Microsoft account linked to your Office 365. Look for the Office/Microsoft 365 product. If it says “Expired” or “Disabled,” you need to renew or reactivate.
Renew your subscription. If your subscription expired, click “Renew” or “Buy now” on the services page. Follow the payment steps. Once payment is processed, your subscription is active again, and Office apps should automatically reactivate within a few hours.
Re-enter your product key (if you have one). If you have a new product key (from a retail card or email), go to account.microsoft.com/services, sign in, and click “Add a new key” or “Redeem.” Enter the 25-character key and follow the prompts. The key will be applied to your account, and your subscription will be active.
Sign out and sign back in to Office apps. Open any Office app (like Word or Excel). Go to File > Account (or Office Account on Mac). Under “User Information,” click “Sign out.” Then click “Sign in” and enter your Microsoft account credentials. This refreshes the activation status.
Run the activation troubleshooter (Windows). If you still see activation errors, download and run the Microsoft Support and Recovery Assistant from aka.ms/SaRA. Choose “Office” and then “I’m having problems activating Office.” Follow the prompts – the tool will detect and fix common activation issues.
Repair Office (Windows). If activation still fails, repair your Office installation. Go to Control Panel > Programs > Programs and Features. Find Microsoft 365 (or Office) in the list, right-click it, and choose “Change.” Select “Quick Repair” (or “Online Repair” if that doesn’t work). This will fix corrupted files that might block activation.
Reinstall Office (if necessary). As a last resort, uninstall Office completely and reinstall it. Go to account.microsoft.com/services, find your Office product, and click “Install.” Download the installer and run it. Sign in with your account when prompted – this should activate the apps.

Common Mistakes

Signing in with the wrong Microsoft account. If you bought Office 365 with one email but sign in with another, you won’t see your subscription. Always use the account that made the purchase.
Not checking the subscription status first. Sometimes the issue isn’t activation but an expired subscription. Renewing fixes it immediately.
Entering a product key with typos. Product keys are case-insensitive but must be exact. Double-check the characters, especially 0 vs O and 1 vs I.
Ignoring “Sign out” step. Simply renewing doesn’t always refresh the license in open apps. Signing out and back in forces Office to check your subscription status.

Tips

Set up recurring billing in your Microsoft account to avoid future expirations. Go to Services & subscriptions, click “Manage” next to your Office, and turn on “Recurring billing.”
If you have a one-year subscription card, redeem it as soon as you buy it. Keys can expire if left unused for too long.
On a Mac, the activation process is similar: sign out from any Office app (under File > Account), sign back in, and if issues persist, use the Microsoft Support and Recovery Assistant for Mac.
Keep your Windows or macOS updated. Outdated operating systems can cause activation errors.

Troubleshooting

“We can’t activate Office” error. This usually means the subscription is expired or the account doesn’t have a license. Check your services page. If it shows active, try signing out and back in.
Office apps show “Product Without a License” or “Unlicensed Product.” This often happens after a Windows update or if you’re using a work/school account that has changed. Run the activation troubleshooter (Step 5) or repair Office (Step 6).
Activation still fails after renewal. Sometimes it takes a few hours for the license to sync. Wait 2-3 hours, then restart your computer and try again.
You can’t sign in to your Microsoft account. Use the password reset link on the sign-in page. If you have two-factor authentication enabled, make sure your phone/email is accessible.
Office is not listed on your services page. If you bought Office 365 from a third-party retailer, you may have received a product key. Redeem it via “Add a new key” on the services page. If you bought it directly from Microsoft, check that you’re signed in with the correct account.

Frequently Asked Questions

How long does it take for Office to reactivate after renewal?

Usually within a few minutes to a few hours. If it doesn’t reactivate immediately, sign out and back in, or restart your computer.

Can I reactivate Office 365 without a product key?

Yes, if you have an active subscription tied to your Microsoft account. Just sign in with that account – no key needed. A key is only required when adding a new subscription.

What if my subscription expired a long time ago?

You can renew it from your Microsoft account services page. If you don’t want to renew, you can still view and print your documents, but you can’t edit or create new ones. Alternatively, you can switch to the free Office Online apps.

Will I lose my files if I reactivate Office?

No. Your files are stored on your computer or in OneDrive, and reactivation doesn’t affect them. You’ll regain full editing ability once active.

Can I reactivate Office on a new computer?

Yes. Sign in with your Microsoft account on the new computer, go to the services page, and click “Install.” You can install Office on multiple devices (usually up to 5) depending on your plan.

What’s the difference between reactivating and reinstalling?

Reactivating means renewing your license or re-entering a product key. Reinstalling means removing and installing the Office software again. You might need to reinstall if the software is corrupted, but first try reactivation.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.