Issue

When trying to log in to activate Microsoft Office 365 apps on a Windows computer, you may get an error that the login failed because another user is already logged in, despite logging in correctly and with an active account.

Resolution

1. Open a Microsoft Office 365 app, such as Word

2. Go to the File menu and select Account on the left
   
   

   Open

   

   Screenshot of Word's File menu highlighting the Account item

   
   
   
   

3. Click Sign Out
   
   

   Open

   

   Screenshot of Word's Account pane highlighting the Sign Out button

   
   
   
   

4. Close and reopen the app

5. Choose to sign in to activate Microsoft Office 365 again