Sergey

The command line string is "assembled" from a mix of drag n' drop and cmdButton code taking values form a listbox.

I have since added CHR(0) to the command line string and managed to get up to 385 characters in the string before the lights went out, but that may be a one off fluke.

I am sure you are right about CreateProcess() - I tend to work on the basis that if it ain't broke, don't mend it, hence sticking with the tried and trusted.