On 7. May 2020, at 12.45, Kishore Potnuru <kishore.reachme@gmail.com> wrote:

Hi All, 

Thank you for your replies and Suggestions. But, I still not clear on my question. But It's live production server. At present I cannot make any changes to it. That will take a long process to make any on this server. At present my concern is, 

To my server (dovecot, postfix, POP3/Imap  protocol), I am getting the emails in my dovecot structured directory "Maildir/new". Once the person/application (example: Microsoft Outlook) read the email, they are moving to "Maildir/cur". If they are deleting the file from Outlook, that will be deleted from the "Maildir/cur" folder also. I have Outlook as an example here. few email boxes are accessed by Outlook and few more email boxes are accessed by an application, where they configure in their application/outlook, to point out my server to read/access the emails. 

I am repeating the same question again, From our server (where postfix, dovecot with pop3/imap protocol installed) knowing any ways (logs, incidents,alerts or any) that Outlook or application read/accessed/deleted the email which is in "Maildir/new" or "Maildir/cur" folder? This is my current issue.

I am sorry for more concerning you guys asking the same question again and again. I am trying find the exact/correct answer on my current issue. I am new to this environment and new to dovecot/postfix also. working from last 3 to 6 months. This environment was designed by some other guy who left the company. I had to take this responsibility to support. I am kind of bit struggling.  Please help. 

And you have already been told the answer. 

mail_log plugin is your friend here. Configure it to log at least "delete undelete expunge" events to log if that outlook deletes the mail. See https://doc.dovecot.org/configuration_manual/plugins/mail_event_logging/

also if you want to check if that outlook does read the mail (ie. mail gets moved from new to cur) you need to configure imap_logout_format and pop3_logout_format to show number of mails fetched. see: https://doc.dovecot.org/settings/core/

Sami