I have similar problem, but in my case search works at some places but does not at others.
Search box in user list - works.
Search dialog which opens on new ticket creation, change user ticket or add collaborator - does not work.
Search box in new ticket form which appears on drop-down under select user - works!
Please, where the SQL logs which some users have posted here come from, so I can look at mine?
Our version is v1.17, on Windows. I recently upgraded from v1.14. Before the upgrade, search worked everywhere.