unable to activate offce 365 business - Microsoft Community Hi, I'm willing to help you Forgive me to confirm your OS and Office product again, Windows 10 and Office 365 for business, right? If so, please try following steps to renew your credentials and reactivate Office 365 1 Sign out all your account from your apps and close all Office apps 2 Click Win+E key Open File Explorer 3 Type this path: Control Panel\All Control Panel Items\Credential