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This article applies to Office Home & Business, Office Professional, and individually purchased Office apps. To switch an Office install to or from Microsoft 365, see Switch your Office license.

Change the product key for your version

How you change the product key depends on your version of Office. Select your Office version from the tabs below.

Best practice for multiple versions of Office

If you bought multiple copies of Office and used the same Install button to install Office on multiple PCs, activation fails on the other PCs. This happens because each Install button is associated with a unique product key that can only be installed on one PC. To fix this, you can change the product key for the other PCs where you installed Office.

Note: After you change your product key, we recommend that you create a list to manage the product keys that you’ve installed. To learn how, see Manage multiple one-time-purchase Office installs that use the same Microsoft account.


  1. Sign in to your Services & subscriptions page with the email and password associated with the Microsoft account that was used to install Office.

    After you sign in, you should see a list of Office products that are associated with your Microsoft account.

  2. For the first product that’s listed on the page, select View product key. Copy or write down the product key. This is likely the product key that was used multiple times to install Office.

  3. Select View product key for the remaining Office products and copy or write them down. These are likely the keys that you’ll use to replace the key that was used multiple times.

  4. On a PC where Office activation is failing, open the Command Prompt as described below:

Windows 10 and Windows 8.1   

Windows 7   

  1. Select the Start button Windows Start button in Windows 8 and Windows 10 (lower-left corner).

  2. Type Command Prompt.

  3. Right-click the Command Prompt icon, and select Run as administrator.

  1. Select the Start button Windows 7 Start button (lower-left corner).

  2. Right-click Command Prompt and select Run as administrator.

  1. Now start an Office app, such as Word, and select Next to activate Office over the Internet.

  2. Repeat this process for each PC where activation is failing.