For problems with windows start command see also my post at DOS script to start UltraEdit
To avoid problems with running a macro from command line while an instance of UltraEdit is already active, run UltraEdit with the macro AND with a special ini-file, also specified at command line. This ini-file could be a simple copy of existing uedit32.ini, but it is important that following setting exists in this ini-file:
The special ini-file for macro execution on command line is named uemacro.ini and stored in the program directory of UltraEdit, which is by default for English windows environment "C:\Program Files\UltraEdit". The command line is now:"C:\Program Files\UltraEdit\uedit32.exe" "Your file to modify.txt" /i="C:\Program Files\UltraEdit\uemacro.ini" /M,E,1="Your macro file with path/macro name"
If you run this from a batch file with the start command, add start "UltraEdit"
at the beginning of the command line above.