How to see a list of indexes in Intellij

I use CLion on a large project. Sometimes, there are number of files that are consistently not indexed. I have tried to invalidatae cache and restart many times to no avail. The only solution is to delete and reinstall Clion. (After each install, after a few days, the index missing issue would come back).

I want to know if I can get a list of the files that are not indexed to debug whether Clion missed indexing those files.