Why you would think things disappearing on your system for synchronization is different from other folks experience with synchronization I have no idea. That is explicitly how IMAP works,

Most of the queries I see about disappearing mail are people using IMAP and then come here because they do not understand synchronize means what happens on the server is replicates locally. So they want to ask why a syncronised services synchronizes and their mail disappears, I see your posting as just another of these.

Your provider undoubtedly deletes SPAM email after a set time. (google I think have a 14 day retention on things in that folder.) Thunderbird by default makes no attempt to download the mail in the spam folder or trash for that matter and synchronize it locally unless you explicitly select the folder to view. When you select the folder, the mail synchronizes and the older garbage is syncronised into oblivion per your providers policy.

You can right click the folder, select properties and set the folder to be included in get mail actions so it is always up to date, but if you are going to do that you probably should do the trash/deleted folder as well as those two folders (Junk and trash) are explicitly not updated unless you select them. Changing the synchronization setting makes no real change to what happens, it will just be you will no longer see it when it happens like you can now.

Hi Matt,

Really appreciate your taking time to answer my question, that was very kind of you to do so. Your answer though is somewhat puzzling given what I am experiencing. Let me explain.

RETENTION (A): I selected the option on Thunderbird that it never deletes e-mails in my junk folder (or any folder). As I have it set-up, only I am supposed to be able do that. So, it is unclear why Thunderbird would delete mails in my junk folder irrespective of IMAP and synchronization you refer to,

RETENTION (B): It is deleting mails, which are incorrectly being directed to my junk folder from work colleagues - which is a whole 'nother issue and problem I have with Thunderbird, that are only a day or two old. I find it hard to believe that any provider network, mine is Comcast, has it to where it is deleting mails that are only a day or two old.

So, I think I did what you suggested. I check marked for both junk and trash the following two options that were not previously checked:

• Include message in this folder in Global Search results.

• When getting new messages for this account, always check this folder.

Please let me know if this is incorrect action.

The issues of IMAP and synchronization you raise is beyond my skill set. But, we have a great IT team at office and I will go through your e-mail with them and test drive it on my work computer that also uses Thunderbird. I will let you know the outcome results,

best regards,

 -  Gareth

Hi Matt,

Unfortunately I am home sick so it may be a few days before I can answer properly regarding your IMAP explanation. But, I wanted to reply because after I implemented your kind suggestion on mail action I discovered the following day that all my missing junk e-mails - about 25 -30 of them, all reappeared out of the electronic ether, all clumped together in my 'sent' folder. Again this seems quite odd first in that they all reappeared as you had indicated that they had probably been be deleted by a provider protocol, and second why all reappear in my 'sent' fold since these are received e-mails not sent e-mails.

Thanks again,

- Gareth