Just for the reference: My solution is as follows: I unpacked latest release+beta+Scite4AutoIt3 from ZIP packages to different directory: "C:\Program Files\AutoIt3312" https://www.autoitscript.com/autoit3/files/archive/autoit/ In "C:\Program Files\AutoIt3" I have got installed my main 3.2.12.1+3.3.7.23+old scite4autoit3 AU3 scripts are opened/ran/compiled in my default 3.2.12.1 editor+autoit+compiler by default (when opened from file manager by Enter or doubleclick).