Each time I want to save a .doc as a plain text file (which is many
many times daily) I get this dialog box:

filename.txt may contain features that are not compatible with Plain
Text format. Do you want to save the document in this format?

Choices are yes, or no and choose a format.

I always want it to be Yes.

Can someone please tell me how to either make the default yes or how
to stop the dialog box from popping up all the time and interfering
with my progress.

Thanks very much for your advice
Joanne