At some point within the past few upgrades (currently on 4.7.11) our quick search stopped working (i.e. you type a name, but the search doesn't yield results as you type) and we've no idea why. How would we even start to troubleshoot and/or resolve this issue?
Thanks Joe for the comment. In the search settings, all of the checkboxes for "Autocomplete Contact Search" were checked. We disabled all but "Contact" (which is set by default) and "Email" and now it's working.