Just create the file [font=courier new]SweetHome3D.l4j.ini[/font] in the same folder as [font=courier new]SweetHome3D.exe[/font]

Hoping that I had understood you correctly, I created a new text file (as shown below), renamed it as:"[font=courier new]SweetHome3D.l4j.ini[/font]", opened it (with r/click > [font=courier new]Edit[/font] ) and inserted the single line:-

"-Dcom.eteks.sweethome3d.singleInstance=false"

then saved it and moved it into the folder containing: "[font=courier new]SweetHome3D.exe[/font]"



Having done that, I can, indeed, now open two instances of the program simultaneously!

Thank you so much for your help (and for your excellent program!). [=D>]

Best Regards. [:D]