Global search auto suggest popup stopped working for a user. Cleared cache, rebooted, logout and back in. Unchecked preferences and recheck them. No other users in the role having issues. Anything else to try, or is this support call?

Sounds like you checked everything. The only time I have someone with that problem is when they have timed out too long on their account login. They need to login but the page still looks open. anything in the global search shows nothing. But you seemed to have cleared everything.