Our targets advance search has recently stopped returning any results and i'm stumped why. We have over 5000 targets in SugarCRM open source Version 4.5.1a (Build 1209) and if we try to do an advance search, we always get no results. I have tried simple searches that I know should give me many results and still get nothing. Simple searches such as 'Last name' start with 'S', I know there are a couple hundred. If I click on the search 'Clear' button, I get full results, but if I click on the search button with or without any criteria, I get no results.

I am looking for advice on how to troubleshoot this.