It's not a questions of extensions.
I right click a folder. There it is. Folders above and below it copy fine.
But random folders with the same name format as the others generate 'Item Not Found.'
My work-around is to make a new folder at the intended destination, and copy the files into it.
(The new folder name has to be the same as the old folder name for export/import purposes.)
I then export this data to a flash drive and take it to an XP machine to burn a CD to deliver to clients.
Pain...
Thanks for asking -
JoeBob