Imap accounts are really a view of what is on server. This type of account is useful if you need to use other methods (another computer or phone) to see all of your received and sent mail. If you delete and email using eg: phone or webmail, then it will be deleted off the server and when Thunderbird synchronises with server, that email will get deleted from Thunderbird imap account because it is not on the server.

Imap accounts can download just headers or full emails. Even if you download full emails, you cannot rely on this being a backup copy in your imap account because imap folders constantly synchronise with server to show what is on server.

Please read IMAP synchronising etc info:

• https://support.mozilla.org/en-US/kb/imap-synchronization

In Imap account you need to subscribe to see the server 'Trash' folder and then you need to make sure you are using it.

• Right click on imap mail account in Folder Pane and select 'Subscribe'
• click on 'Refresh'
• select the server Trash folder - it might be called something similar.
• click on 'Subscribe'
• click on 'OK'

• Right click on imap mail account in Folder Pane and select 'Settings'
• Select 'Server Settings'

When I delete a message:

• select 'Move it to this folder'
• and select the subscribed Trash folder on the imap mail account.

Under Message storage section: If required you can select to empty the trash on exit, but you may not want this.

• click on 'OK'

Restart Thunderbird

Please note that some servers auto empty the server Trash folder periodically. eg: Gmail does it approx every 30 days.

The 'Trash' is really a temp holding place just in case you need to undelete an email, but in general it is assumed by server that all emails put in Trash are no longer wanted or needed. It is not advised to use this folder if you are unsure about deleting or need to store the email.

If you need to keep an email, but do not want to keep it on the server, then copy the email into a suitable folder in 'Local Folders' mail account before deleting it off server. Note: if you 'move' an email from imap folder to Local Folders then it will be deleted off the server. I prefer to copy the emails and then delete them. If an email is not fully downloaded when you 'move; the email, then you may only see headers and the email can get lost because the only copy is on the server.

Regardless of whether you use Pop or IMAP it is advisable to create a backup of the ....\Roaming\'Thunderbird' folder: C:\Users\<Windows user name>\AppData\Roaming\Thunderbird Do this after downloading/ synchronising imap folders and whilst Thunderbird is not running.

This is confusing... The Trash folder setting is still not working, should I just go back to POP? What are the disadvantages, because this is getting me confused! LOL!

Never mind. It works if I move to Archive <G>

Thanks for your help!

goonybird said

What is the best setting to delete them from the server but NOT on Thunderbird?

given IMAP is synchronised, you have only two choices.

Move all mail to local folders and it will by default be deleted from the server or use POP. I use POP because IMAP is a mail protocol, not a filing system and does not cope will with large scale moving of mail