When I got my smart back in January, it took me an extra 45 minutes to get off the lot, because I opened the engine cover and then couldn't get it to lock. A technician replaced the latch, but it had the same problem. The solution turned out to be as simple as applying strong downward pressure at the latch point, and then twist. It was not a matter of 'seating' the cover properly, and could not be resolved by wiggling the cover, in my case.