Sometimes when I close Mach 3 I get a box that says save" fixture settings? " what is it asking me to save
Thanks Bill

Sometime during your last session, one (or more) of the fixture offsets had been changed.
Mach3 will notice that (those) changes and ask if you want them saved replacing the originals.
If no changes were made, you would not get that prompt.

They are your WORK offsets.

Russ