Which version of LFFTS are you using? How large your catalog is? Please post a screenshot of the search folder if possible. It is unusual to take so long to finish optimization, especially when LFFTS just uses 1GB  of memory. And for 'Optimization ran for 3 weeks', what exactly did you see? Sometimes LFFTS performs incremental optimization, or it can schedule optimizations on idle time. And sometimes optional optimizations might be canceled for insufficient resources, or user activities. So what you saw could be several small optimizations instead of a single one. The messages in Windows Event Log might provide more information about optimization.