Pending, as usual, an elegant answer from the informed … one approach could be to create a new ToC in the book file, import the reference pages (where the selection mechanism lives) from the renamed ToC and then generate the new one again. HTH
Question is unclear. What needs fixing?
Is this a TOC file that was renamed by means other than the book menu, and now doesn't work?
If the TOC file is in book, and works, you can rename it from the book menu (which is the only way to auto-update both the book and all the references in other book component files). Select TOC file. Right-click rename.
Does the file exist, and have exactly the same name as it appears in the book file (letter case and all)?
Frame's book menu normally can open a formerly-generated file even if it doesn't recognize it as generated any more.