Overview

When deleting or moving items through IMAP protocol, the designed behavior is to mark messages for the performed action. The resulting behavior in some IMAP clients is to display these marked messages with a strikethrough. For most users, this behavior is not preferred, so Kerio Connect compensates by automatically performing (expunging) the marked action.

For example, in the case of Apple Mail, the user is not presented with a strikethrough, and the performed action (move/delete) appears to the user as completed, however it does not ask the server to perform the expunge action. As a consequence of Kerio Connect automatically performing the expunge action, the Undo option in Apple Mail does not work; in this particular case, AutoExpungeOnDelete should be toggled OFF.

Another potential behavior is that if an email is deleted from Outlook, then this email may show up in the Deleted emails/Trash folder twice; in this particular case, AutoExpungeOnDelete should be toggled OFF.

Step-By-Step Guide

The Auto-expunging Mechanism is by default enabled in Kerio Connect and it is not managed through the UI; this means that if you change the behavior, it may get reverted after an upgrade.

To edit the automatic expunge feature, you need to manually edit the mailserver.cfg file using the below steps:

1. Stop the Kerio Connect Service.
   1. Starting or Stopping the Kerio Connect Server on Windows
   2. Stopping and Starting the Kerio Connect Service on macOS and Linux
2. Open the install directory and locate the mailserver.cfg file
   1. Modifying the mailserver.cfg
3. Open the file in a text editor and search for the string AutoExpungeOnDelete.
   

   <table name="Imap">
     <variable name="AutoExpungeOnDelete">1</variable>
   </table>

4. Change the value to 1 or 0, depending on the behavior you desire (default value is 1)
5. Start the Kerio Connect Service.

Summary

Changing the AutoExpungeOnDelete value from will alter the behavior of the IMAP delete commands in order to match your requirement.

FAQ

1. Will I have to change the `AutoExpungeOnDelete` value again during the next upgrade?
   It's not certain. Monitor the situation after the next upgrade and if the issue reoccurs, repeat the steps provided.
2. Can this behavior occur with Microsoft Office?
   This issue has been reported with Microsoft Office versions 2016, 2019, and 2021. If you experience this issue with other versions, follow the steps provided, as they would apply to any Office version when using IMAP.
3. Can this behavior occur with other mail clients?
   Yes, we've had a few reports with Apple Mail syncing emails via IMAP, albeit that the behavior was different when compared to Outlook, as Apple Mail handles the IMAP DELETE command differently