Does the project have multiple TOC's and that she opened the wrong one? That would be the easiest explanation.
Perhaps RoboHelp somehow lost track of the TOC files. Which files with the .hhc extension are saved on her machine?
Did your client rename the project, removed the CPD file or work from a network drive?
She had two (an old one and a new one). We actually opened both files. I actually saw the TOC files. The .hhc extension files were on her machine. When we opened them, the content was gone.
No she did not rename the project, or remove the CPD file or work from a network drive.
Sounds like a “restore from backup” situation…
I'll let her know.