Hi Alec, this works for me,

I cannot save my plot file as .TXT, I am using LTspiceIV
Is that the cause ?

Regards Guus

 

If you first click on the plot window, then look in the File menu, don't you have the 'Save data as text' option? You do in LTspice XV11.

 

I downloaded LTspiceXVII but stil can save only as .PLT file

 

Did you click on the plot window, then look in the File menu? The data export item is the tenth one in the menu. Sorry if I misled you saying 'save' instead of 'export'.