How does the deduplicator currently work?

It would be nice to have a base-line on how the deduplicator is now supposed to be working. In my case using version 8.2.1687. If you restore a backup eM Client immediately goes to the email accounts and downloads everything on the server, which doubles up what you’ve moved to local folders. Then running the deduplicator (to try to get rid of those doubled up) for some reason moves just about everything, including emails for which there only exists one copy? By the way, when it’s moving it deletes off the server, so then even if you have a backup, you restore the backup and the email has still disappeared?

This is a real mess. When I look up in this forum back in Feb there’s a post not to use it? … then sometime later says it’s okay to use? … doesn’t appear okay to me … makes me wonder what other landmines I’m about to step upon.

Anyone’s help would be greatly appreciated. Thank you!

Assuming the MAC version?

Yes, sorry, should have mentioned that.