Thank you for your answer, Thorsten Sorry, Thorsten, I am not quite understand. What do you mean by "swapped D7 with another LCD pin". Soldering checked several times. I have LCD connector crimped two times . I make LCD cable shorter. Such behavior exists when LCD is disconnected and all PIC pins connected to the air. I just TOUCH (not plug) CORE:J15 by LCD connector and it goes into reboot. Probably, you mean, if all pins are soldered and connected well PIC gets unreceptive to static ? I am using same cables and same connectors for RA, RC, RD ports, and those ports dont mind about static.... PS: PIC18F452 (MIOS 1.7/Midibox2.3)