I think that's how the POP3 mail protocol works.  If there's an IMAP option (I haven't looked), then that should leave messages on the server, even after they've been retrieved/viewed.

Hi Jeff,

there is an IMAP option, but what I want is the following:

Until now, I used POP3 email for the main email (contact@mycompany) so that all employees get the emails on their mail application. I dont want to use IMAP, because with IMAP the message will be marked as read at the moment, the first employee opend the mail. So each mail client asked the server for new mails and downloaded them if or if not anybody else already did this.

So if it is possible to stop odoo deleting the mails by downloading them, I get the behavior I expected.

@Marcel Just

How POP3 works, each user email app (for example Thunderbird, Outlook, etc.) keeps track individually, locally, of the "newest" email message it has received, and which emails messages are "read" or "unread".  Each user would have a personalized experience of what is the new email messages, and what is read/unread.

For IMAP, you are right, it is a shared email inbox, and as soon as anyone reads a message, it would appear modified (read/unread).

I think you're missing the point of Odoo messaging, relative to shared incoming email inboxes. For example, the inbox support@yourcompany.  You probably don't want tthose messages coming into many employee inboxes.  You probably want Odoo to automatically create a new record of type Helpdesk  (crm.helpdesk), and have the Helpdesk record automatically assigned to whichever group of emplyees is intended to handle the customer helpdesk.