Cuantos pdf se pueden asociar a un storyline?

Hello Eloisa, 

Thanks for reaching out! 

There's no limit to the number of resources you can include in a Storyline 360 course, so your files should definitely not stop loading after 37 PDFs. 

Would you be willing to share a copy of your project file here or in private by opening a support case so we can take a closer look at what's happening? We'll delete it when we're done testing!