"Switching your SEF on a mature website can be very costly, since some of your URLs will change, and that can cause you to lose a lot of previous SEO work. It can worsen your Search Engine page position and reduce your traffic. It is important to chose the right SEF component early in the life of your site." - pintobuck Switching SEF components have many drawbacks, that is the reason why I've developed OpenSEF to Artio JoomSEF Migrator. This component will backup your OpenSEF database tables and insert all OpenSEF URLs into JoomSEF as custom URLs. Which Might be the solution for your problems. OpenSEF component has been abandoned by its developers and, althought it is a great component, JoomSEF seems to be better, at least in my point of view. The Migrator has been developed for and tested with OpenSEF 2.0.0-RC5_SP2, however it should work with NuSEF. Enjoy :^) Joomla API: - PHP Cross Reference of Joomla 1.5 Documentation - http://apostilas.fok.com.br/docs/joomla-1.5/ - PHP Cross Reference of Joomla 1.0 Documentation - http://apostilas.fok.com.br/docs/joomla-1.0/