How to Download, Install and Activate Office 2021 Professional Plus for Windows – Retail or OEM

How to Download, Install and Activate Office 2021 Professional Plus for Windows – Retail or OEM Guide

If you’re looking for how to download, install and activate Office 2021 Professional Plus for Windows, this step-by-step guide has everything you need. This version of Office activates using a one-time key that does not bind to a Microsoft account. Once activated, your Office license is valid for lifetime use on the same PC.

Quick Summary

  • Step-by-step instructions for downloading Office 2021 Professional Plus for Windows
  • How to install Office 2021 using .exe file or .img file
  • Activation using a one-time product key
  • Troubleshooting tips for common activation problems
  • Easy access to additional support via email, WhatsApp or Click to Start a Chat

 

How to Download Install and Activate Office 2021 Professional Plus for Windows - Two License Options

Step 1: Make sure you have Microsoft account

You’ll need a Microsoft account to download the latest Installation file (for Retail version).

👉 Don’t have one? Create a free account at: https://account.microsoft.com/account

Step 2: Prepare your Office 2021 Professional Plus License

🛒 Don’t have a license yet?

✅ Order Office 2021 Professional Plus for Windows – OEM

✅ Order Office 2021 Professional Plus for Windows – Retail

🧾 Important Information & limitation:

One key can be used only one time for one activation on one installation. Once activated, Office 2021 Professional Plus is licensed for lifetime use on that installation. If you need to reinstall in the future on the same or a new machine, you’ll need to purchase a new key.

Step 3: How to Download Office 2021 Professional Plus for Windows

Option 1:  Retail Version – Download via Microsoft Setup Page

  1. Go to https://setup.office.com
  2. Sign in with your Microsoft account (used for access only – license will not bind)
  3. Enter your product key
  4. Select your language and version
  5. Click Download

 

Option 2: OEM Version – Download Using the Direct Download (.img File)

Download the official Microsoft .img file

You can also install additional languages later by going to:
File → Options → Language → Add a Language

🌐 Other Available Languages

 

Step 4: How to Install Office 2021 Professional Plus

Option 1: Retail Version

  1. Run the downloaded .exe installer
  2. The Office installer will launch — follow the prompts
  3. Office will install automatically (usually in C:\Program Files\...)
  4. Installation typically takes 5–10 minutes depending on your system

After installation, you’ll find the Office apps (Word, Excel, PowerPoint, etc.) in your Start Menu.

 

Option 2: OEM Version

1. Mount the image file

  • Locate the .img file you downloaded
  • Double-click it to mount it as a virtual CD
  • If it doesn’t open automatically:
  • Open File Explorer
  • Go to This PC
  • Look for the new virtual CD/DVD drive and open it

 

🛠️ Other Ways to Mount a .img File in Windows

✅ Option 1: Use the Right-Click Menu

  1. Right-click the .img file
  2. Choose “Mount” from the context menu

 

If “Mount” isn’t listed, try Option 2 or 3 below.

✅ Option 2: Use File Explorer’s Ribbon Menu

  1. Select the .img file
  2. At the top of File Explorer, go to the Manage / Disk Image Tools tab
  3. Click Mount

 

✅ Option 3: Use Windows PowerShell

  1. Right-click Start and open Windows PowerShell (Admin)
  2. Run this command:
  3. Mount-DiskImage -ImagePath "C:\Path\To\Your\File.img"
  4. Replace the path with the actual location of your .img file.

 

✅ Option 4: Use Third-Party Software (if needed)

If none of the above work, you can use free tools like:

 

These tools create a virtual drive and automatically mount the .img file when opened.

Step 5: How to Activate Office 2021 Professional Plus

  1. Open any Office app (like Word or Excel)
  2. Go to File → Account → Activate Product
  3. Choose “I have a product key”
  4. Enter your 25-character product key
  5. Click Activate
  6. Once activation is successful, you’ll see:
    “Product Activated”

 

🎉 That’s it — Office 2021 Professional Plus is now fully installed and activated on your Windows PC!

Troubleshooting Activation Issues

❌ Activation failed

  • Solution: Double-check for typos when entering the key and your internet connection. Make sure you’re installing the correct version (Office 2021 Professional Plus).

❌ Setup won’t run or install fails

  • Solution: Reboot your PC and run the installer again. Make sure you don’t have other versions of Office installed, only one version of Office must be installed on one machine.

💬 Still having problems?

Our support team is available 24/7 — reach out any time:

Final Notes

Office 2021 Professional Plus (one-time activation) is permanently licensed to the installation where it’s activated. If you uninstall, reinstall or switch devices later, a new license key will be required.