I've got ten instances of MT4 running on my PC right now. Six of them have one chart open, the other four have four charts open. What I did was download MT4 from FXDD and then installed it ten times, each time in it's own directory, with "nice" names like "Euro_15m" etc.... Each instance got its own demo acct number, login ID and password when I started it up the first time. I'm testing an EA on all four majors on four different timeframes. (Four of the MT4's are Multi_5m, Multi_15m and so on, where multi means more than one chart) What I'd like to know is if there is a "set path" type of command in MT4 to have all ten of my MT4's use the one same EA file, so that I can make changes, fix errors etc in only one file and not have to copy it nine times....