Today is Friday, April 9. Conference was 5 days ago. The Conference talks appear in Gospel Library on churchofjesuschrist.org - but have not loaded into my Windows Desktop app. I have updated everything that I can see to update.
I was struggling with this same issue, and the suggestion made to delete the April Conference and download it again worked. I just wanted to thank the author of the suggested response for his suggestion. Thank you! It worked.