With Boost theme, OneTopic course returns an error when attempting to open from the Dashboard. If you open the Drawer you can then access both Courses contents.
This can be caused by a combination of the behaviour of the OneTopic format and the course in question having a section highlighted that no longer exists. The OneTopic format is trying to render the highlighted topic by default and it's generating that error when it can find it.
- Change the course format to Topics
- Pick any topic, click the edit menu, and click "Highlight" to make that topic the highlighted one.
- [Optional] click "Edit" again and click "Remove Highlight".
- Change the course format back to "OneTopic"