If you selected "prevent skipping", but when you check one of your students' progress reports and it seems like they skipped parts of the video, don't worry. :)
The student is probably using a smartphone or a tablet to watch the lesson. It is harder to track the students when they use these devices, which is why we have Apps for iOS and Android. Make sure the students use one of the following:
1. iPhone and iPads: Edpuzzle iOS App
2. Android Smartphone or Tablet: Android App
3. Laptops: Chrome, Firefox or Safari (latest version)
If they are using these correct devices and versions, progress should be tracked much more effectively. If you continue to have this problem, please let us know at firstname.lastname@example.org and we'll take a look!