Office 2016 Mac Key Already Used

• Buy Office 2016 For Mac
• Activate Office 2016 Mac
• Microsoft Office For Mac 2016

It gives you Office 2013 on PCs and the same license allows you to install Office 2008 on Mac computers as part of the 5 allowed installations. The Mac version will be upgraded 'for free' and automatically when the new Mac version is released. It currently costs US$100 per year. Hi HermieL, it would probably be best to uninstall and re-install Office, if you are getting a 'Product Key already used' error. You need to deactivate your previous Installation and then re-install Office 2016 Go to and sign in using your Microsoft account, if prompted.

Buy Office 2016 For Mac

Symptoms

In Microsoft Outlook 2016 for Mac, you are repeatedly prompted for authentication while you're connected to your Office 365 account.

Cause

This issue occurs because of the presence of duplicate tokens in the keychain.

Resolution

To resolve this issue in Outlook 2016 for Mac, install the February 2017 Outlook update (version 15.31.0) from the following Office website:

Workaround

To work around this issue, delete any cached passwords for your account, and also delete any modern authentication tokens from the keychain. To do this, follow these steps.

Note

These steps affect all Office applications that use modern authentication.

1. Quit Outlook and all other Office applications.

2. Start Keychain Access by using one of the following methods:

   • Select the Finder application, click Utilities on the Go menu, and then double-click Keychain Access.
   • In Spotlight Search, type Keychain Access, and then double-click Keychain Access in the search results.

3. In the search field in Keychain Access, enter Exchange.

4. In the search results, select each item to view the Account that's listed at the top, and then press Delete. Repeat this step to delete all items for your Exchange account.

5. In the search field, enter adal.

6. Select all items whose type is MicrosoftOffice15_2_Data:ADAL:<GUID>, and then press Delete.

7. In the search field, enter office.

8. Select the items that are named Microsoft Office Identities Cache 2 and Microsoft Office Identities Settings 2, and then press Delete.

9. Quit Keychain Access.

   Note

   When you start Outlook, you are prompted to authenticate.

Symptoms

In Microsoft Outlook 2016 for Mac, you are repeatedly prompted for authentication while you're connected to your Office 365 account.

Cause

This issue occurs because of the presence of duplicate tokens in the keychain.

Resolution

To resolve this issue in Outlook 2016 for Mac, install the February 2017 Outlook update (version 15.31.0) from the following Office website:

Workaround

To work around this issue, delete any cached passwords for your account, and also delete any modern authentication tokens from the keychain. To do this, follow these steps.

Activate Office 2016 Mac

Note

These steps affect all Office applications that use modern authentication.

Microsoft Office For Mac 2016

1. Quit Outlook and all other Office applications.

2. Start Keychain Access by using one of the following methods:

   • Select the Finder application, click Utilities on the Go menu, and then double-click Keychain Access.
   • In Spotlight Search, type Keychain Access, and then double-click Keychain Access in the search results.

3. In the search field in Keychain Access, enter Exchange.

4. In the search results, select each item to view the Account that's listed at the top, and then press Delete. Repeat this step to delete all items for your Exchange account.

5. In the search field, enter adal.

6. Select all items whose type is MicrosoftOffice15_2_Data:ADAL:<GUID>, and then press Delete.

7. In the search field, enter office.

8. Select the items that are named Microsoft Office Identities Cache 2 and Microsoft Office Identities Settings 2, and then press Delete.

9. Quit Keychain Access.

   Note

   When you start Outlook, you are prompted to authenticate.