I've been using Gmail for quite a while and I have about 15000 emails in total, only partially sorted using labels. Using Gmail itself to sort them is a nightmare for me, so I decided to use Thunderbird instead. My plan was to download the emails (IMAP, not POP3) and move them to a local folder to store them and have them removed from Gmail. I assumed the emails disappear from Gmail if I move them to a local folder, but that seems to be only true if you move the email from the Inbox, and not "All Mail".
Here is my problem: I had the emails in Gmail sorted using labels. I removed all those labels from the conversations and I expected all my emails would land back in my inbox, but they didn't. They are all visible under "All Mail" from what I saw, but they're not in the Inbox. The Inbox has a fraction of the amount of emails that "All Mail" has.
Where did the emails go? All I want is to move all my emails to a local folder on Thunderbird and have them removed from Gmail automatically, but I can't do that, because the "All Mail" folder/label seems to be a copy of all the emails, so if I move those, the emails are still in Gmail.
Best Answer
Every new email received has the special label "inbox" unless you use a filter to prevent it from receiving the "inbox" label. The user can attach other labels as they see fit, which is a strength of Gmail becasue that message can have multiple labels.
If a user clicks the archive button the "inbox" label is stripped from the message/conversation, but it leaves the other labels attached to that message.
If a message has no labels becasue no other labels had been attached before the "inbox" label was removed, then it is only found in the "all mail" category becasue that category shows you all your messages in your Gmail account.
Removing other labels from a message/conversation doesn't automatically move them to the inbox becasue that would involve reattaching the "inbox" label. This can be done using the labels button.
Each message only appears once in Gmail. It can have 0, 1 or many labels. In fact messages in Gmail don't move, they just have labels, and the software uses the various queries to show them to the user.