I have a big problem with the function Dynamic. For example this short line of code "Dynamic[DateString, UpdateInterval -> 1]" always stops after some time (2 minutes, 10 minutes,...). I have sent this issue to Wolfram. They say it is a known problem (I am not the only one who has reported it) but they have not discovered the reason jet. The problem appears in both versions M8 and M9. Any suggestion or idea?