To delete a dvi filename from the File menu in Menu Bar and the history (File->History), select the file from File->History, press [Hide], then quit dviout. The next invocation of dviout does not show the filename on the File menu.
If dviout is killed by File->Quit, the dvi history record is not updated.
These techniques are useful after reading dvi files from floppy disks and other removable media.