Well, first of all, hello everyone, I’m new here and as well in Aseprite, so my question can be dumb or easy to fix.
I’m trying to export a RBGA format png file, in Aseprite x64 1.2.9 (Steam)
But it doesn’t seem to work, and it seems to work when the program wants, since when changing the file name or destination, sometimes it works.
I’m doing something wrong?
I’m not sure if I understand. What happens when it doesn’t work?
If the problem is the color mode of the resultng “png” file then you can use this:
Sprite>Color Mode > RGB Color
And then this:
File File>Save As>[write or select “png” extension]
I hope this helps! 
Since the “error” seems only to appear randomly, i will try what you said. Thanks!