The font embedding process using the Univeral embedding method can succeed completely or fail, depending on the presentation file you chose and on the fonts it uses.
When the embedding process succeeds, a green circle with a check mark will appear on the presentation thumbnail. This means that all fonts have been embedded and that a new presentation file containing the embedded fonts has been created. Clicking the linked filename will open a new Finder window and select the new file.
In cases where the fonts could be embedded (e.g. the app could not find or communicate with Microsoft PowerPoint, the file was read-only, other error, or etc.), a red circle with an X mark will appear on the presentation thumbnail.
The main title of the window will provide you with information for the failure.