Microsoft Office 2021 Professional Plus Download: How to Download, Install & Activate

This guide covers how to download Microsoft Office 2021 Professional Plus, install it on your Windows PC, and activate it with your genuine licence key. Office 2021 Pro Plus is a one-time purchase that includes Word, Excel, PowerPoint, Outlook, Publisher, Access, and more.

🔑 Buy a genuine Office 2021 Professional Plus key from LicenceHouse — instant delivery, guaranteed activation.

System Requirements for Microsoft Office 2021 Professional Plus

• OS: Windows 10 or Windows 11 (64-bit recommended)
• Processor: 1.6 GHz, 2-core minimum
• RAM: 4 GB (64-bit), 2 GB (32-bit)
• Storage: 4 GB available disk space
• Display: 1280 x 768 resolution at 150% DPI or less
• Internet: Required for installation and activation
• .NET version: .NET 4.6 or later

How to Download Office 2021 Professional Plus

Method 1 – Download via Microsoft Official Installer

1. Visit the official Microsoft Office 2021 page.
2. After purchasing your licence key, sign in to your Microsoft account.
3. Navigate to Services & Subscriptions or Office and click Install.
4. The Office installer (Setup.exe) will download automatically.
5. Run the installer and wait for Office 2021 to download and install.

Method 2 – Download via Office Deployment Tool (ODT)

For advanced users or IT administrators deploying Office 2021 on multiple machines:

1. Download the Office Deployment Tool from Microsoft.
2. Create a configuration.xml file specifying Office 2021 ProPlus edition and 64-bit architecture.
3. Run: setup.exe /download configuration.xml
4. Then install: setup.exe /configure configuration.xml

How to Install Office 2021 Professional Plus

1. Run the downloaded Office installer (OfficeSetup.exe).
2. Click Yes on the User Account Control prompt.
3. Office will automatically download and install the latest version.
4. Wait for the progress bar to complete (typically 5–20 minutes depending on internet speed).
5. Once complete, click Close and launch any Office application.

How to Activate Microsoft Office 2021 Professional Plus

Online Activation (Recommended)

1. Open any Office application (e.g., Word, Excel).
2. Click Activate when prompted, or go to File → Account → Activate Product.
3. Select Enter a product key instead.
4. Enter your 25-character product key in the format XXXXX-XXXXX-XXXXX-XXXXX-XXXXX.
5. Click Continue and follow the prompts to complete activation.

Phone Activation (Offline)

If your PC has no internet connection, use phone activation:

1. Open Command Prompt as Administrator.
2. Navigate to Office directory: cd C:\Program Files\Microsoft Office\Office16
3. Run: cscript ospp.vbs /act
4. Follow the on-screen instructions to call Microsoft's activation hotline.

💡 LicenceHouse also offers Office 2021 phone activation keys for offline systems.

Troubleshooting Office 2021 Activation Errors

Error: "This product key has already been used"

Contact LicenceHouse support immediately. If you purchased a genuine key, it may need to be reset by our team.

Error 0x8007007B – Invalid File Name Syntax

1. Open Command Prompt as Administrator.
2. Run: cscript "%ProgramFiles%\Microsoft Office\Office16\OSPP.VBS" /ipk YOUR-KEY
3. Then run: cscript "%ProgramFiles%\Microsoft Office\Office16\OSPP.VBS" /act

Office 2021 Not Activating After Reinstall

Run the Office Repair tool: Control Panel → Programs → Microsoft Office 2021 → Change → Quick Repair.

Frequently Asked Questions

Is Office 2021 a one-time purchase?

Yes. Office 2021 Professional Plus is a perpetual licence — you pay once and own it forever. It does not expire and does not require a subscription.

Can I install Office 2021 on multiple PCs?

A standard Office 2021 Pro Plus key is licensed for 1 PC. For multiple devices, purchase additional keys from LicenceHouse.

What's included in Office 2021 Professional Plus?

Word, Excel, PowerPoint, Outlook, Teams, OneNote, Access, Publisher, Skype for Business, and OneDrive integration.

Does Office 2021 work on Windows 10?

Yes. Office 2021 is fully compatible with both Windows 10 and Windows 11.

Where to buy a genuine Office 2021 Pro Plus key?

Buy Microsoft Office 2021 Professional Plus from LicenceHouse — genuine keys, instant delivery, best price guaranteed.

Related Guides: Office 2024 Pro Plus Download Guide | Windows 11 Pro Download Guide