Actually it seems to be a larger problem :
On my account, microsoftMicrosoft or local, that existed before the upgrade cortanaCortana does not find Apps or settings. It now finds my documents after rebuilding the index.
It doesn't search in "Settings" either. And even worstworse, outside cortanaCortana, the search in the "Settings" panel search box finds nothing, even if the searched text is in the current search page!
On a newly created local adminadministrator account, just for test, it works like a charm.
MightIt might be an access right-right issue somewhere.
Emmanuel