Why is the search field in System Settings returning no results after updating to macOS 15 Sequoia?

I have an M3 Max 16" MacBook Pro. I updated it to macOS 15.1 (from 14.7) yesterday evening. The search bar in System Settings is no longer returning any result after updating. Typing anything in it returns the message "No Results". . Do you know what may have caused this and what could be the cure? On Apple Discussions there is someone who has solved it by deleting and restoring the User, apparently advised by Apple Support, but I am not going to do that. What is the process governing this search? Perhaps there is some indexing still to be done?