Looking for the Microsoft Office Professional Plus 2021 official download and a simple way to install and activate it? This complete step-by-step guide shows you exactly how to download, install and activate Microsoft Office 2021 Professional Plus on your PC using a genuine product key — including a direct download link from Microsoft’s official servers. Office 2021 is a one-time purchase with lifetime activation and no subscription.

What You’ll Need

• A genuine Office 2021 Professional Plus product key — emailed in seconds when you buy Office 2021 Professional Plus.
• A Windows 10 or Windows 11 PC. The office 2021 professional plus download 64-bit version is recommended for modern machines.
• About 4 GB of free disk space and an internet connection for activation.

Step 1: Get Your Genuine Office 2021 Product Key

Buy a genuine Microsoft Office 2021 Professional Plus licence. Your 25-character product key is emailed within seconds of checkout, 24/7, along with the download link. Every key is genuine and activates directly on Microsoft’s servers — a one-time purchase, not a subscription.

Step 2: Download Office 2021 Professional Plus

There are two ways to get the Microsoft Office Professional Plus 2021 official download. Both come straight from Microsoft.

Method 1: Download via your Microsoft account (recommended)

1. Go to setup.office.com and sign in with a Microsoft account (create a free one if needed).
2. Enter your 25-character Office 2021 product key.
3. Choose your language and select the 64-bit version for most PCs (choose 32-bit only for older hardware).
4. Click Download and save the installer.

This method links the licence to your Microsoft account, which makes reinstalling on a new PC much easier later.

Method 2: Direct download from Microsoft’s official CDN

Prefer a direct Office 2021 offline installer? You can download the official Office 2021 Professional Plus Retail disc image (.img) straight from Microsoft’s content delivery network — no account sign-in needed to download:

How to use the .img file: right-click the downloaded ProPlus2021Retail.img and choose Mount (Windows 10 and 11 can open .img files natively). A virtual drive opens — run Setup.exe from inside it to begin the Office 2021 installation.

Step 3: Install Office 2021 Professional Plus

1. Run the installer (or Setup.exe from the mounted .img).
2. Let it install Word, Excel, PowerPoint, Outlook, Access and Publisher — this takes a few minutes.
3. When you see “You’re all set!”, the install is complete.

Tip: uninstall any older Office version or trial first to avoid conflicts.

Step 4: Activate Office 2021 with Your Product Key

1. Open any Office app, such as Word.
2. Sign in with your Microsoft account if prompted, or choose Enter product key.
3. Type your 25-character key to complete Office 2021 activation.
4. Confirm under File › Account — it should say “Product Activated”.

How to Activate Office 2021 Offline

No internet on that PC? Open an Office app, go to File › Account › Change Product Key, enter your key and follow the telephone activation prompts to activate Office 2021 by phone. Once the PC is online again, activation confirms automatically.

32-bit or 64-bit: Which Should You Install?

Choose the 64-bit version on any modern Windows 10 or Windows 11 PC — it handles large Excel files and heavy documents far better. Only pick 32-bit if you run very old hardware or depend on legacy 32-bit add-ins. The direct download above is the 64-bit English retail image.

Troubleshooting: Office 2021 Won’t Activate

My Office 2021 product key won’t activate

Check that you’re online, signed in with the right Microsoft account, and that the key is typed exactly with no extra spaces. If it still fails, contact our support team — we’ll replace the key or refund you in full.

“This product key has already been used”

Each licence covers one PC. If you reinstalled Windows or changed hardware, sign in with the same Microsoft account and reactivate — the licence stays linked to your account.

The installer stops or fails midway

Temporarily pause antivirus, make sure you have 4 GB free space, then re-run Setup.exe. Using the offline .img avoids most download interruptions.

Can I move Office 2021 to a new computer?

Yes — it’s a perpetual licence. Uninstall from the old PC, then reinstall and reactivate on the new one with the same key and Microsoft account.

Office 2021 System Requirements

Office 2021 Professional Plus runs on Windows 10 and Windows 11 with a modern 64-bit processor, 4 GB RAM (8 GB recommended), 4 GB of free disk space, and an internet connection for download and activation.

Frequently Asked Questions

Is Office 2021 Professional Plus a one-time purchase?

Yes — a perpetual licence with lifetime activation, not a Microsoft 365 subscription. Pay once, keep it forever.

Where can I get the official Office 2021 Professional Plus download?

Either sign in at setup.office.com and redeem your key, or use the direct Microsoft CDN link above to download the official ProPlus2021Retail.img offline installer.

Is the direct download link safe?

Yes — it points to officecdn.microsoft.com, Microsoft’s own content delivery network. You still need a genuine product key to activate the software.

What’s included in Office 2021 Professional Plus?

Word, Excel, PowerPoint, Outlook, Access and Publisher.

How long does the install and activation take?

Roughly three minutes on a normal broadband connection.

Does Office 2021 Professional Plus work on Mac?

No — Professional Plus is Windows-only. On macOS, choose Office for Mac instead.

Do I need to uninstall my old Office first?

Yes, we recommend removing any previous Office version or trial before installing Office 2021 to prevent activation conflicts.