Occasionally, for no known reason, course menu items will become hidden. This will prevent students from viewing your content and will result in numerous emails complaining of the issue. In order to correct the issue, please follow these steps:
1. Using the contextual menu, toggle the availability off and then on again by using the "Hide Link" or "Show Link" option. This will often clear the problem.
IF this doesn't correct the problem....
2. Create a new course menu item by clicking on the "+" symbol at the top of the course menu and choose the appropriate menu item you wish to have. Most commonly this will be a Content Area or Tool Link.
Name the menu item and check the box to make it available to students.
This will then display in the course menu. You will then want to move the content items from the unusable content area to this new one.
To move content, use the dropdown selection beside the content item title and choose "Move". From the Move window, click 'Browse' under the Destination section and choose the course menu content area you just created and named (hopefully a little different!!). Complete these steps until all content is moved. Delete the unusable course menu item.
This should correct any content viewing issue you or your students have in the course.