Why? Its not a folder that you store mails in, its part of an IMAP accounts setup. In IMAP mails are kept on server and a synchronize MUST take place to let you delete, move, etc so your server folder and your T-bird folders show the same mails.

We have 2 computers in our house that have access to the same emails.

We have 1 email account that has a Synchronisation & Storage setting/folder. It is rubbish. None of our other email accounts has this setting. We did not ask for it. How can we get rid of it.

The problem . When an email is opened on 1 computer it shows on the 2nd computer that is has been opened. Hence the who ever turns on there computer first gets to see what new emails have come in and the other user doesn't.

When 1 computer deletes the email the other computer deletes as well again its rubbish.

That's the difference between an IMAP-account and a POP3-account. IMAP-mail are stored on the server, so you can access them from different units. If you read, move or delete you do this to the original on the server.

A copy can be kept in inbox on your device, but unless you copy, not move, to a local folder it will be synchronized.

POP3-mail on the other hand are downloaded to a device like your PC and deleted from server Here you can do whatever you want with them.

If you set your pop3-account up to keep mails on server, you also have to tell when to delete. Or your server-folder will be filled with all mails, real and spam.

POP3- mail is harder to synchronize between devices as all must be set up equally or one may start downloading and delete from server.

Question: when will you consider a mail read or deleted?