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My situation is the following: I have a Google Mail email-address and I have been using this address in Thunderbird fetching the emails with POP3 (the emails also remained on the server and where "archived"). In Thunderbird I organized my emails in folders.
Now I want to switch to IMAP (with the same email address), but I want to keep the folder structure I created in Thunderbird.
I could create a 2nd account in Thunderbird that uses IMAP, and then move my folders from the old account to the new one. But the problem is, that Google Mail probably does not recognize that it already has these moved emails in "All Mails". I will probably end up with two copies of every email.
Does someone has good idea how to deal with that problem?