When looking at the Dashboard, if students seem to be missing files or folders inside their TD subject folders, then it's usually one of two issues:
1. There's an issue with the TD Subject Folder.
Teachers can fix this problem themselves:
1. Open the class
2. Click the Class Info tab.
3. Click the "Fix class folders" link.
Note that it can take up to 30 minutes to restore the folders.
2. The files have been Smart-shared as read-only and won't display in TD
See the Hapara help article here for an explanation.