Install and activate Microsoft Office 2021

Office 2021 is a one-off purchase without a subscription: you pay once and use the programs permanently on one device. Installation runs over the internet; there is no disc. This guide describes the route for the retail version and explains at the end what is different with a volume licence.

Which edition did you buy?

The whole procedure depends on it, and the two routes have nothing in common. Our order confirmation says which edition you have:

• Home & Business is a retail licence. The licence key is redeemed once at setup.office.com in a Microsoft account; the download and the activation then run through that account. The next sections describe this route.
• Standard and Professional Plus are volume licences – both of them, not only Professional Plus. They cannot be redeemed at setup.office.com and never appear in a Microsoft account; trying it there ends in an error message. You install from the download link in our email and enter the licence key afterwards from the Command Prompt. For that, skip straight to the section further down that describes the volume licence.

Requirements

• Windows 10 or Windows 11, 64-bit, with updates installed.
• Around 4 GB of free space.
• A Microsoft account – free to create at account.microsoft.com.
• The 25-character licence key from your order confirmation.
• Remove older Office versions first under Settings → Apps → Installed apps.

Step 1: Redeem the key

1. Go to setup.office.com.
2. Sign in with your Microsoft account. Choose an account you will have permanent access to, because the licence is permanently tied to it.
3. Type in the licence key or paste it from the email.
4. Select your country and language. Both affect only the first download.
5. Confirm. Office 2021 then appears in your account under Services & subscriptions.

Step 2: Download the installation

1. Open account.microsoft.com and switch to Services & subscriptions.
2. Click Install next to Office 2021. The further options let you set the language and the bit version; if in doubt, stay with the 64-bit variant.
3. Run the downloaded file and confirm the User Account Control prompt.
4. The installer downloads the programs in the background. Leave the computer switched on and online while it does so.
5. When it has finished, start Word or Excel and sign in with the same Microsoft account.

Step 3: Check the activation

In any Office program, open File → Account. On the right, under Product Information, you can see which product is installed and whether it has been activated. If a note about a required activation appears there, click Sign in and use the account you redeemed the key with.

Retail or volume licence

With retail licences everything runs through the Microsoft account, as described above. A volume licence – with us that means Office 2021 Standard and Office 2021 Professional Plus – is not redeemed online. In this case you obtain the installation files through the Office Deployment Tool from Microsoft, and the key is only entered locally after installation. This is done from a Command Prompt with administrator rights:

1. Change to the installation folder, usually Program Files\Microsoft Office\Office16.
2. cscript ospp.vbs /inpkey:YOUR-KEY enters the key.
3. cscript ospp.vbs /act carries out the activation.
4. cscript ospp.vbs /dstatus shows the status.

With a volume licence, no entry appears under Services & subscriptions in the Office account view – this is normal and not a fault.

If something goes wrong

• “This key is not valid”: Check for typing errors, especially 0 and O as well as 1 and I. Copying and pasting is the safest approach.
• Setup stops with an error code: This is usually caused by leftovers from an earlier Office installation. Microsoft offers a tool on its support pages for removing Office completely.
• Office starts only in reduced functionality mode: The activation is missing. Sign in under File → Account, or, with a volume licence, check the output of ospp.vbs /dstatus.
• The wrong language was installed: Language packs can be added afterwards without reinstalling Office.
• The download is extremely slow: A different browser or a wired connection instead of Wi-Fi often helps.

If you cannot get any further, contact us via our contact page. Give your order number and the exact wording of the error message.