Followup - The download proceeds from either one of the links in my original
post with ample & clear instructions on the install process, and there are
easily found instructions for disabling the add-on.
I found that the delete-duplicates settings are important - too tight
(especially w/r to the lengths of apparently identical emails) and the S/W
says, "no duplicates" - and some emails are closely timed (within a minute),
have the same numbers of lines, but really are different. Emails with
attachments are rarely flagged as duplicates ... care required, lest we save
the corrupted one and remove the good one ... so I have been allowing those
that don't have precisely the same send times to remain even if they are
flagged as duplicates.
The S/W can be set to work on only the selected folder and not on any
subfolders. That seems like a cautious approach ... I used that method, and
removed maybe 50,000 duplicates from about 500 folders in less than an hour.
Thanks for your encouragement !
