How i delete a folder?

Hi basic question i can’t find…

How can i delete a folder…or delete all messages from a folder?

I have version 5.803

You cannot delete a folder from K9 Mail, its more meant to work as a receiver, which is the same reason it does not let you create filters and macros.

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Oh…so also no way to create a folder like “unknown” for all mails that are exactly unknown as long as I mark them?

That doesn’t seem to be what the developer thinks. Seems K-9 Mail is the only app/program anyone will use for email and therefore it will control everything, or at least this is the reason for not supporting POP.

That’s not quite correct. POP is actually intended to work with only one client; using multiple clients is actually kind of a hack.

POP stands for “Post Office Protocol,” which is a pretty accurate analogy for how it works. In its intended use case, an email inbox behaves like a literal, physical post box. The mail carrier / email server sticks mail into it, then you / your mail client removes that mail from it. By default, retrieving mail from the server deletes it from the server. This is fundamentally incompatible with using multiple mail clients, as the first one to connect will “win” and get all the pending mails. This would lead to your mails being split among your clients somewhat randomly, which is not a good outcome. There’s also the concern that cketti raised, which is that having your phone contain the only copy of your emails is a recipe for data loss. All it takes is dropping your phone down a storm drain and now all your emails are lost. Not a great outcome, and certainly a nasty shock for the unaware.

In order to work around this issue, POP servers / clients added a hack: retrieve the mails but do not delete them from the server. This way, all clients have the chance to pull down the mails, even if they are not the first. The problem is that the POP protocol doesn’t have any way for clients to send information back to the server. Thins like read state, starring, folders…none of that can be synchronized. Thus, if you mark a mail as read on your phone, it will remain unread on your other clients. If you move a mail into a folder on your phone, it will remain in the inbox on your other mail clients. This is not a limitation of K-9, it’s simply impossible to do with the limits of POP.

I’ll briefly address one point people often raise with POP, that being the ability to delete mails off the server as soon as they are received. Some people seem to think this is a security or privacy win, but this is simply wishful thinking. Deleting a mail via the POP protocol in no way assures that the mail provider has not retained another copy of the message. Even Google admits as much, mentioning in their support docs that deleted mails may persist in backups for upwards of two months. And if the concern is an attacker stealing your account password, deleting and expunging mails to make them inaccessible via the standard email protocols is just as possible via IMAP.

In summary, the default behavior of POP is potentially dangerous in that it could lose mail, and the workaround behavior necessarily causes desync between clients if they try to use even basic features of modern email clients like read state or stars. I’m personally fully in support of dropping POP support. I would wager (though I have no data to back this up) that for ever one user on this forum claiming they prefer the POP workflow, there are hundreds of users out there constantly confused by the fact that they read an email on their phone and then the web interface still shows it as unread.


None of that is an issue. I know how POP works, the fact remains it is ludicrous to remove POP support just because someone thinks it doesn’t work when it actually does. Doesn’t matter that the “leave mails on server” is a hack, it works so that’s that. What has syncing got to do with it? I don’t want mail synced, that’s one of the reasons I use POP. IMAP is a total mess on that front, I never get calls about POP not working, always having issues with IMAP syncing/stuck folders, sync speeds…

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Me too. I don’t use my phone the same way I use my computer so I don’t want messages synced between the two devices, so I use pop. I also like pop because it doesn’t seem to have a many errors in use. Another benefit of pop not mentioned is that I have my own offline copy of all my emails in case the server ever becomes temporarly unavailable to me for any reason, or in the future, permanently. One suggestion for developers would be to ask the user base if they use a feature before cutting support because you don’t use it. Has this already happened with another lost, beloved feature of k-9 (hint: accounts overview screen)?. 8_)