Before opening Revit navigate to your Autodesk Account Profile using web address: manage.autodesk.com/home.
Login to your Autodesk Account.
Click “All Products and Services” on the left hand side ribbon under Products and Services drop-down menu.
Click on “View Details” located underneath the Revit Install button.
Click on the year version of Revit you are using.
Click the “Extensions” tab located underneath the Available Downloads heading.
Download Interoperability Tools (version number) for Revit (year specified).