I found a post from years ago with that title, but since the discussion is locked and I have an 840 not an 820, I thought I'd repost with an updated title. I've had the freezing problem with my 840 that others have mentioned in this group, but I've finally narrowed it down to the RCT715. Using that tail light is the only time the 840 screen freezes. Hopefully Garmin has an update coming soon that fixes this...