I've seen this....it has nothing to do with running with an internal oscillator. You don't need the internal clock running, or an external for that matter (I think) to program the part (it probably defaults to exernal anyway) since the data is clocked into the part by the programmer. I've done 18F4680 and 16F913 both with internal clocks and they program fine and run under the debugger. One thing I've noticed with my dev setup, running USB and winXP, is that MPLAB sometimes forgets about the ICD hanging out there. For example if the laptop drops into sleep or standby, and I bring it back up, I will have to exit from MPLAB, and unplug the ICD from the USB port and then bring MPLAB back up, plug the ICD back in (that order) and it will find the ICD and program correctly. You might try fooling with that, if I come across this error again with my setup, I'll let you know. Its just one of those things that I've seen, but if I recall it had nothing to do with the firmware or target device. If anyone else can ID this error....probably should put it into the FAQ ?? Lee McLaren wrote: MPLAB ICD 2 Ready Resetting Target MPLAB ICD 2 Ready ICD0154: Invalid target mode for requested operation (TM = Running) ICD0151: Failed to sync memory (MT = Data) (Dir = 0x0) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist