The .asv file extension is used by Finale notation programs for auto-saving files. This file extension is used by some other programs as well, notably Adobe Photoshop. Since Windows can only associate one program at a time with a particular file extension, it may ask you which program you want to use. Choosing Yes will associate .asv files with Finale notation programs, and choosing No will keep the file type associated with whatever program to which it was previously set.
This is not expected to alter the architecture of these files, but will change the choice of what program your operating system associates with that file. Meaning it may change what program opens those files by default and what icon appears for those file types.