Purchased a Microsoft Office product key and not sure what to do next? The process has changed over the years — you no longer insert a disc or run a setup file from a package. In 2026, all Office installations are done through Microsoft’s servers, and your product key is what unlocks them. Here’s the complete step-by-step guide.
Before You Start: What You’ll Need
- Your 25-character Office product key (format: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX)
- A Microsoft account (free to create at account.microsoft.com)
- A stable internet connection (the installer downloads approximately 3-6 GB)
- At least 4 GB of free disk space (10 GB recommended)
If you purchased your key from VexoKey, it was delivered to your email immediately after checkout. Check your inbox (and spam folder) for an email with your key and any activation instructions specific to the edition you bought.
Step 1: Redeem Your Product Key at Microsoft
- Open your browser and go to setup.office.com
- Sign in to your Microsoft account. If you don’t have one, click Create a free account and complete the signup — it takes about two minutes.
- On the setup page, you’ll be prompted to enter your product key. Type the 25-character key exactly (hyphens are usually added automatically).
- Select your country/region and language, then click Next.
- Microsoft will validate your key and associate it with your Microsoft account. You’ll see a confirmation screen showing which Office product you just redeemed.
Important: Once you redeem the key to your account, it is linked permanently. Make sure you’re signed in to the correct Microsoft account before redeeming.
Step 2: Download the Office Installer
- After redeeming, you’ll be redirected to your Microsoft account’s Services & Subscriptions page (or you can navigate there directly at account.microsoft.com/services).
- Find your newly redeemed Office product in the list and click Install (for Office for PC) or look for the Mac download option if you’re on macOS.
- A file called OfficeSetup.exe (Windows) or Microsoft_Office_installer.pkg (Mac) will download. This is a small bootstrapper — the actual Office files download during installation.
Step 3: Run the Installer
On Windows:
- Double-click OfficeSetup.exe from your Downloads folder.
- If Windows asks for permission (UAC prompt), click Yes.
- The Office installer launches automatically and begins downloading the Office apps. This process typically takes 10-30 minutes depending on your internet speed.
- Do not close the installer window or restart your PC during this process.
- When finished, you’ll see a message confirming that Office has been installed.
On Mac:
- Open the downloaded .pkg file from your Downloads folder.
- Follow the on-screen prompts — click Continue, agree to the license terms, and click Install.
- You may be prompted for your Mac user password to authorize the installation.
- Once complete, open any Office app (Word, Excel, etc.) from your Applications folder.
Step 4: Activate Office
- Open any Office application — Word is the easiest to start with.
- On first launch, Office will prompt you to sign in. Sign in with the same Microsoft account you used to redeem the key.
- Office will check your account, find the redeemed license, and activate automatically. You’ll see a welcome screen confirming activation.
- To verify: click File > Account (or Word > About Word on Mac). You should see your Microsoft account email and the product name listed as activated.
Troubleshooting Common Issues
“This product key has already been used”
This means the key was already redeemed to a Microsoft account. Sign in to account.microsoft.com — if it’s your account and you see the Office license there, just download and install from the Services page without re-entering the key. If you purchased from VexoKey and believe the key was already used before you received it, contact VexoKey support immediately for a replacement.
Activation Error 0xC004F074 or 0x8007007B
These errors usually indicate a network issue preventing Office from reaching Microsoft’s activation servers. Temporarily disable your firewall or VPN, then try activating again. If the issue persists, try the phone activation option in the activation troubleshooter.
Office Is Installing in the Wrong Language
Go to account.microsoft.com/services, click the Office product, and look for language options before downloading the installer.
Supported Office Versions Available at VexoKey
VexoKey carries genuine keys for all major Office versions with instant delivery:
- Office 2024 Professional Plus — the latest perpetual release
- Office 2021 Professional Plus — stable and widely supported
- Office 2019 Professional Plus — for compatibility with older systems
- Microsoft 365 Personal — always up-to-date subscription
Frequently Asked Questions
Can I install Office on more than one PC with one key?
Standard Office 2021 and 2024 retail keys are licensed for one PC or Mac. Microsoft 365 Personal covers one user on up to five devices. If you need Office on a second PC, you’ll need a separate license key. VexoKey sells keys individually so you can purchase exactly what you need.
Do I need internet to use Office after installing it?
Office 2021 and 2024 (perpetual licenses) work fully offline after activation. You need internet only for the initial download and occasional license verification (once every 30 days or so). Microsoft 365 requires internet connectivity at least once a month to verify the active subscription, though you can work offline between verifications.
What if I reinstall Windows — do I lose my Office activation?
No. Because your Office license is linked to your Microsoft account, reinstalling Windows and signing back in to Office with the same account automatically restores your activation. You do not need to re-enter the product key.
Can I transfer my Office license to a new PC?
Retail Office licenses (like those sold by VexoKey) are transferable. To move to a new PC: uninstall Office from the old PC, then install on the new one and sign in with your Microsoft account. The license follows your account. OEM licenses (pre-installed by manufacturers) are not transferable.