(1) Eventually used File Explorer to delete all "dwsync.xml" files everywhere.
(2) Completely uninstalled then reinstalled DW.
(3) Reloaded DW then loaded single php page from a site.
(4) Pressed space bar to insert single space at end of first line.
(5) Received message: "Access denied to xxxx.php".
(5a) But now slight improvement because not getting string of amorphous messages re "dwsync.xml" files
(6) But cannot edit then save any site files whatever. All getting same "Access denied message".