just got a nuvi 255w. After i updated maps from the website, it failed to locate the satellites no matter where I place it. Before the update, everything was good.
had the same problem ... then ... updated software [again, had updated it before buying map updates] then walked out into park area with GPS and waved it at the open sky - somewhat in desperation but suddenly it spoke to me "drive to highlighted route" ... now seems to be working OK
Sorry for the high tech nature of this "solution" :)
