When creating a course from a PowerPoint you have the option to include the Master Slide design as a Page background image in Claro. This option will take the Master Slide design of the PowerPoint and convert it into an single image which is placed in the bottom layer of each page that is created from the PowerPoint slides. The image will be locked so it is not accidentally deleted or removed. This image will cover any background theme color or graphic on these pages. Unlocking and deleting an individual background image or adding a new page will reveal the inherent embedded theme background.
While including the background will create a course with pages that most closely represent the PowerPoint, the best approach is to use PowerPoint files with no MasterSlide background design or ones that match a Claro Theme and then choose to not include the background when importing the PowerPoint. This will provide you with the most optimal and flexible course design and make it easier to update and maintain your course when changing your Theme or adding new pages.