Learn@UW - Student Downloading and Course Materials (UW-Madison)
Students can download any file you post to your course website. While there is no way to prevent students from downloading content files that you have uploaded to D2L and made accessible, you can be thoughtful in how you make your content available to students.
With this in mind there are ways to deliver course content that decreases the chance of unsanctioned use. An instructor can, for instance, project information or content from a laptop or thumb drive during lecture instead of posting it on the website. (Though even in this case, students could still potentially take pictures of the content). An instructor can upload documents to their course website and attach release conditions to the documents to ensure that student's cannot access or download the documents until completing a selected action (More information on release conditions Here) An instructor can also hide content from students using the "draft" feature of D2L (More information on hiding content Here) However, once an instructor has made a document available to students, the students will be able to download that document. The only way to guarantee students cannot download a document is to not upload it to the course website, or not make it available to students on the course website.