How to change SyncState without duplicating every message?

[Alan S. <ala...@po...>]

Hello,

I want to change my configuration to `Syncstate *' for all my
channels. I tried on a couple and it worked great, but after checking
outside of notmuch (which does not show duplicates), I realized every
email is now duplicated, both locally and on the server. I tried a
deduplication tool, but the presence of a different header X-TUID makes
the duplicates different. I have two questions:
- is there a way to remove all these duplicate emails?
- for the last channel to migrate, how can I make sure emails are not
duplicated (ideally without having to download them again)?

Thanks,

Alan